WEBVTT FILE 1 00:00:00.000 --> 00:00:03.005 (dramatic music) (plane engine roars) 2 00:00:02.000 --> 00:00:07.000 Downloaded from YTS.MX 3 00:00:03.005 --> 00:00:04.680 (gunfire popping) (water splashes) 4 00:00:04.680 --> 00:00:07.870 - [Narrator] The outcome of World War II is at stake. 5 00:00:07.870 --> 00:00:11.020 Over 400 American and Japanese warships 6 00:00:08.000 --> 00:00:13.000 Official YIFY movies site: YTS.MX 7 00:00:11.020 --> 00:00:12.220 do battle at Leyte Gulf. 8 00:00:13.175 --> 00:00:16.269 - It was the largest naval action in history. 9 00:00:16.269 --> 00:00:17.590 (light music) 10 00:00:17.590 --> 00:00:19.800 - [Narrator] Japan is counting on a secret weapon 11 00:00:19.800 --> 00:00:22.233 the Americans know almost nothing about, 12 00:00:23.200 --> 00:00:26.430 except her name, Musashi. 13 00:00:26.430 --> 00:00:29.100 - You'll find, in the summer of 1944, 14 00:00:29.100 --> 00:00:32.210 the naval intelligence experts groping 15 00:00:32.210 --> 00:00:35.120 for an understanding of these huge ships. 16 00:00:35.120 --> 00:00:37.630 - [Narrator] At 72,000 tons, 17 00:00:37.630 --> 00:00:40.610 she's the largest battleship ever built. 18 00:00:40.610 --> 00:00:42.860 - She's not just 10% bigger than some 19 00:00:42.860 --> 00:00:45.870 of these other vessels, she's nearly double. 20 00:00:45.870 --> 00:00:48.770 - [Narrator] Bristling with anti-aircraft batteries 21 00:00:48.770 --> 00:00:51.037 and massive 18-inch guns. 22 00:00:51.037 --> 00:00:52.856 (guns banging) 23 00:00:52.856 --> 00:00:55.500 - You can't believe all the firepower 24 00:00:55.500 --> 00:00:57.563 that comes up at one time. 25 00:00:58.460 --> 00:01:01.487 - [Narrator] Her builders boast, "She's unsinkable." 26 00:01:02.610 --> 00:01:05.270 Yet, in her first major fight, 27 00:01:05.270 --> 00:01:09.170 this super battleship is sent crashing to the ocean floor. 28 00:01:09.170 --> 00:01:13.420 (water splashing) (metal creaks) 29 00:01:13.420 --> 00:01:16.422 But mysteries have always surrounded Musashi. 30 00:01:16.422 --> 00:01:18.210 (dramatic music) 31 00:01:18.210 --> 00:01:21.610 Now, Americans and Japanese researchers 32 00:01:21.610 --> 00:01:25.665 are joining forces to unlock her most stubborn secrets. 33 00:01:25.665 --> 00:01:27.955 (graphics whirring) 34 00:01:27.955 --> 00:01:29.880 (Hirotada speaks in foreign language) 35 00:01:29.880 --> 00:01:30.780 - [Interpreter] This front part 36 00:01:30.780 --> 00:01:32.863 is where flooding is taking place. 37 00:01:35.150 --> 00:01:39.563 - [Narrator] Why did an unsinkable giant go down so fast? 38 00:01:40.460 --> 00:01:42.830 Was it overwhelming American air power 39 00:01:43.890 --> 00:01:46.090 or a fatal design flaw that sent 40 00:01:46.090 --> 00:01:49.303 nearly 1,000 Japanese sailors to their death? 41 00:01:50.951 --> 00:01:52.240 (Masahiro speaks in foreign language) 42 00:01:52.240 --> 00:01:54.450 - [Interpreter] Hundreds of people are crying for help 43 00:01:54.450 --> 00:01:58.792 in horrified voices as they were all sucked into the waves. 44 00:01:58.792 --> 00:02:01.320 (plane engine roars) 45 00:02:01.320 --> 00:02:04.400 - [Narrator] To unravel the mysteries of Musashi, 46 00:02:04.400 --> 00:02:07.883 the missing giant must first be found. 47 00:02:09.602 --> 00:02:12.998 (water gurgling) 48 00:02:12.998 --> 00:02:15.609 (waves splash) 49 00:02:15.609 --> 00:02:18.020 (light music) 50 00:02:18.020 --> 00:02:21.630 In February 2011, a research vessel 51 00:02:21.630 --> 00:02:23.570 begins a three week expedition 52 00:02:23.570 --> 00:02:26.523 in the Sibuyan Sea of the Central Philippines. 53 00:02:28.100 --> 00:02:30.450 - You know, if this was anywhere else, 54 00:02:30.450 --> 00:02:32.690 all the coastline would have been changed 55 00:02:32.690 --> 00:02:35.010 with buildings and high-rises and all sorts of things. 56 00:02:35.010 --> 00:02:37.690 And that's not the case here, so we know we're looking at 57 00:02:37.690 --> 00:02:39.040 basically what the pilots 58 00:02:39.040 --> 00:02:43.600 saw 70 odd years ago. (flash bulb popping) 59 00:02:43.600 --> 00:02:45.430 - [Narrator] The expedition is the brainchild 60 00:02:45.430 --> 00:02:48.833 of the late Paul Allen, co-founder of Microsoft. 61 00:02:50.910 --> 00:02:53.210 The son of a World War II veteran, 62 00:02:53.210 --> 00:02:55.290 Allen committed significant resources 63 00:02:55.290 --> 00:02:58.593 to searching for the war's most iconic missing shipwrecks. 64 00:02:59.530 --> 00:03:02.033 Among them, the mysterious Musashi. 65 00:03:03.465 --> 00:03:05.810 (ship crew chattering) 66 00:03:05.810 --> 00:03:09.593 Rob Kraft is in charge of conducting all sub sea operations. 67 00:03:10.773 --> 00:03:12.240 (guns bang) 68 00:03:12.240 --> 00:03:14.510 - Musashi was the pride of the Japanese fleet. 69 00:03:14.510 --> 00:03:16.820 It was so important to the Japanese people 70 00:03:16.820 --> 00:03:19.131 that they didn't even inform the population 71 00:03:19.131 --> 00:03:20.413 that it has sunk. 72 00:03:20.413 --> 00:03:22.890 - Lots of people would like to find the Musashi. 73 00:03:22.890 --> 00:03:24.230 It's one of the great battleships, 74 00:03:24.230 --> 00:03:26.700 it's one of the truly remarkable ones 75 00:03:26.700 --> 00:03:28.031 that haven't been found. 76 00:03:28.031 --> 00:03:29.300 That is-- - I think there's something-- 77 00:03:29.300 --> 00:03:31.070 - [Narrator] David Mearns has made a career 78 00:03:31.070 --> 00:03:32.893 out of hunting for lost shipwrecks. 79 00:03:32.893 --> 00:03:35.160 (soft dramatic music) 80 00:03:35.160 --> 00:03:36.930 After months spent combing 81 00:03:36.930 --> 00:03:40.510 through military archives in the US and Japan-- 82 00:03:40.510 --> 00:03:42.170 - [David] And what it's showing you here. 83 00:03:42.170 --> 00:03:43.980 - [Narrator] He's identified the critical clues 84 00:03:43.980 --> 00:03:46.260 he hopes will lead them to Musashi. 85 00:03:46.260 --> 00:03:48.550 - The key is that one. 86 00:03:48.550 --> 00:03:49.922 - [Narrator] One is visual, 87 00:03:49.922 --> 00:03:51.130 (flash bulb pops) 88 00:03:51.130 --> 00:03:54.020 aerial photographs taken by American pilots 89 00:03:54.020 --> 00:03:55.993 during their final devastating attack. 90 00:03:55.993 --> 00:03:58.348 (flash bulb pops) 91 00:03:58.348 --> 00:04:01.020 - [David] There's the plane coming in lining up 92 00:04:01.020 --> 00:04:04.040 right there to attack Musashi 93 00:04:04.040 --> 00:04:06.616 and this is the next frame in the sequence. 94 00:04:06.616 --> 00:04:09.516 You can no longer see the plane, but we see a torpedo hit. 95 00:04:09.516 --> 00:04:11.470 (flash bulb pops) 96 00:04:11.470 --> 00:04:13.450 - [Narrator] Clearly recognizable in the background 97 00:04:13.450 --> 00:04:15.880 of these photographs, is the outline 98 00:04:15.880 --> 00:04:18.833 of Sibuyan Island a few miles to the south. 99 00:04:21.350 --> 00:04:22.450 - [Rob] Outside this circle? 100 00:04:22.450 --> 00:04:23.400 - [David] Outside the blue circle. 101 00:04:23.400 --> 00:04:24.233 - [Rob] Outside the blue. 102 00:04:24.233 --> 00:04:25.403 - [David] Yeah, yeah. 103 00:04:26.310 --> 00:04:27.840 - [Narrator] But there are other clues 104 00:04:27.840 --> 00:04:30.733 that may narrow down the search even further. 105 00:04:32.390 --> 00:04:34.590 - And the most important one came 106 00:04:34.590 --> 00:04:37.250 from one of the destroyers, the Japanese destroyer 107 00:04:37.250 --> 00:04:40.740 that was ordered to stand by Musashi. 108 00:04:40.740 --> 00:04:44.633 Kiyoshimo actually took a position for Musashi sinking. 109 00:04:45.830 --> 00:04:47.390 - [Narrator] Using the position reported 110 00:04:47.390 --> 00:04:49.460 by the destroyer, Kiyoshimo, 111 00:04:49.460 --> 00:04:51.180 Mearns and Kraft have determined 112 00:04:51.180 --> 00:04:53.143 a high-probability search area. 113 00:04:55.280 --> 00:04:57.320 The tool selected for the search 114 00:04:57.320 --> 00:05:00.370 is called a multibeam echosounder. 115 00:05:00.370 --> 00:05:03.373 It's a type of sonar that's mounted on a ship's hull. 116 00:05:04.330 --> 00:05:07.850 An array of downward-looking beams emitting sound waves 117 00:05:07.850 --> 00:05:09.550 sweeps across the seabed 118 00:05:09.550 --> 00:05:11.994 to create an image of a mile-wide swath. 119 00:05:11.994 --> 00:05:13.850 (soft dramatic music) (water gurgling) 120 00:05:13.850 --> 00:05:17.350 - We're over here on the western side of our box. 121 00:05:17.350 --> 00:05:20.070 We're running the first line to the east 122 00:05:20.070 --> 00:05:23.290 and this happens to be line number 13. 123 00:05:23.290 --> 00:05:26.273 And each line should take about four hours. 124 00:05:27.360 --> 00:05:28.820 - And because we're looking for, 125 00:05:28.820 --> 00:05:30.430 in the terms of the depth of the water, 126 00:05:30.430 --> 00:05:32.090 quite a small target. 127 00:05:32.090 --> 00:05:35.730 We're mapping the seabed in very, very high detail. 128 00:05:35.730 --> 00:05:39.560 So the byproduct of our search is a really detailed map 129 00:05:39.560 --> 00:05:41.763 of this particular part of the Philippines. 130 00:05:42.920 --> 00:05:44.860 - [Narrator] Even though Musashi is as big 131 00:05:44.860 --> 00:05:49.740 as a 75-story building, the battleship will only show up 132 00:05:49.740 --> 00:05:53.453 as a small speck on this vast and unexplored seafloor. 133 00:05:54.750 --> 00:05:57.053 There's no guarantee she can be found. 134 00:05:58.810 --> 00:06:00.910 - It all depends on her orientation on the bottom, 135 00:06:00.910 --> 00:06:04.040 if she's in one piece, two piece, three pieces. 136 00:06:04.040 --> 00:06:05.920 We should be able to detect that and see them 137 00:06:05.920 --> 00:06:08.000 in what they call the backscatter imagery. 138 00:06:08.000 --> 00:06:09.100 When you hit something hard, 139 00:06:09.100 --> 00:06:11.303 it shows up as a very, very dark object. 140 00:06:12.492 --> 00:06:14.909 (soft music) 141 00:06:16.190 --> 00:06:17.560 - [Narrator] It takes four days 142 00:06:17.560 --> 00:06:19.853 to cover the high-probability area. 143 00:06:22.110 --> 00:06:25.630 It yields an impressive picture of the seabed below, 144 00:06:25.630 --> 00:06:27.973 including a newly discovered seamount. 145 00:06:29.310 --> 00:06:32.573 But so far, there's no sign of Musashi. 146 00:06:33.520 --> 00:06:36.630 - So our highest probability to begin with 147 00:06:36.630 --> 00:06:40.540 was all on the basis of this Japanese destroyer, Kiyoshimo, 148 00:06:40.540 --> 00:06:43.210 which gave a precise sinking position. 149 00:06:43.210 --> 00:06:44.840 It's now very clear that 150 00:06:44.840 --> 00:06:48.220 that position wasn't as accurate as I had hoped. 151 00:06:48.220 --> 00:06:51.220 And the cost of that, we're now having to expand the search. 152 00:06:53.174 --> 00:06:54.840 (soft dramatic music) 153 00:06:54.840 --> 00:06:57.540 - [Narrator] Their focus shifts to the second, 154 00:06:57.540 --> 00:06:59.389 albeit less precise clue-- 155 00:06:59.389 --> 00:07:00.740 - That's the bow. 156 00:07:00.740 --> 00:07:02.280 - [Narrator] The aerial photographs taken 157 00:07:02.280 --> 00:07:04.843 by the American planes attacking Musashi. 158 00:07:05.810 --> 00:07:08.120 - I mean, I think if we go down here, 159 00:07:08.120 --> 00:07:09.880 we're gonna be able to, we're gonna be able 160 00:07:09.880 --> 00:07:10.820 to get a better feel. 161 00:07:10.820 --> 00:07:11.653 - [Rob] Yeah. 162 00:07:13.070 --> 00:07:14.870 - [Narrator] This cardboard box, 163 00:07:14.870 --> 00:07:16.550 which has the same field of view 164 00:07:16.550 --> 00:07:19.110 as the camera the airmen used, 165 00:07:19.110 --> 00:07:22.793 allows Mearns to get a close approximation of what they saw. 166 00:07:23.880 --> 00:07:26.340 - Musashi would be about two kilometers closer 167 00:07:26.340 --> 00:07:29.467 to the island from here when these photographs were taken. 168 00:07:29.467 --> 00:07:30.300 (flash bulb pops) 169 00:07:30.300 --> 00:07:32.693 And she sinks four hours later. 170 00:07:34.030 --> 00:07:36.810 - [Narrator] With the evidence gleaned from the photos, 171 00:07:36.810 --> 00:07:40.160 they plot a new series of sonar runs. 172 00:07:40.160 --> 00:07:42.620 - That's what we've covered, that red line there. 173 00:07:42.620 --> 00:07:45.170 Anywhere outside of that, she could be. 174 00:07:45.170 --> 00:07:47.920 - I would almost bias it further to the west, 175 00:07:47.920 --> 00:07:49.377 because in that photograph, 176 00:07:49.377 --> 00:07:50.210 (flash bulb pops) 177 00:07:50.210 --> 00:07:52.390 she's clearly heading westerly 178 00:07:52.390 --> 00:07:54.730 as opposed to north. (flash bulb pops) 179 00:07:54.730 --> 00:07:56.362 - [Narrator] But the clock is ticking. 180 00:07:56.362 --> 00:07:57.660 (flash bulb pops) 181 00:07:57.660 --> 00:07:59.745 The expedition only has two weeks left 182 00:07:59.745 --> 00:08:02.282 to find the mystery ship. 183 00:08:02.282 --> 00:08:04.700 (soft dramatic music) 184 00:08:04.700 --> 00:08:08.003 Musashi was first conceived in the 1930s, 185 00:08:08.003 --> 00:08:09.370 (gun popping) 186 00:08:09.370 --> 00:08:12.680 a time when Japan's efforts to expand it's territory 187 00:08:12.680 --> 00:08:15.960 and influence in Asia and the Pacific 188 00:08:15.960 --> 00:08:19.070 were increasingly blocked by it's former ally, 189 00:08:19.070 --> 00:08:20.393 the United States. 190 00:08:21.440 --> 00:08:25.330 - Japanese national prestige had been dealt an insult 191 00:08:25.330 --> 00:08:27.110 by the Washington Naval Treaty. 192 00:08:27.110 --> 00:08:28.260 Just to put it in numbers, 193 00:08:28.260 --> 00:08:30.770 the treaty created circumstances where 194 00:08:30.770 --> 00:08:33.960 for every 100 United States warships that are built, 195 00:08:33.960 --> 00:08:36.550 the Japanese are permitted 60. 196 00:08:36.550 --> 00:08:38.850 It created a future in which the Japanese Imperial Navy 197 00:08:38.850 --> 00:08:41.180 was going to be numerically inferior 198 00:08:41.180 --> 00:08:42.623 to the United States Navy. 199 00:08:44.250 --> 00:08:46.730 - [Narrator] In response, a powerful faction 200 00:08:46.730 --> 00:08:49.563 begins advocating for a different strategy. 201 00:08:50.642 --> 00:08:53.750 (Toshiya speaks in foreign language) 202 00:08:53.750 --> 00:08:54.790 - [Interpreter] Japan, at the time, 203 00:08:54.790 --> 00:08:56.728 had neither the resources nor the budget 204 00:08:56.728 --> 00:08:58.990 to build a large number of battleships 205 00:08:58.990 --> 00:09:00.463 to fight against the US. 206 00:09:03.370 --> 00:09:05.820 So they decided to counter quantity with quality. 207 00:09:07.690 --> 00:09:09.490 That was the idea they came up with. 208 00:09:10.510 --> 00:09:13.740 - [Narrator] Quality meant constructing giant battleships 209 00:09:13.740 --> 00:09:16.673 that could overcome the enemy's larger numbers. 210 00:09:18.150 --> 00:09:21.140 The new battleship was called the Yamato-class 211 00:09:21.140 --> 00:09:22.643 after it's prototype. 212 00:09:23.890 --> 00:09:27.440 To win public support, this navy handbook likens it 213 00:09:27.440 --> 00:09:30.962 to a powerful figure in a popular movie of the time. 214 00:09:30.962 --> 00:09:33.712 (sinister music) 215 00:09:37.370 --> 00:09:39.410 (crowd screaming) 216 00:09:39.410 --> 00:09:42.810 The Hollywood film about a giant ape creating mayhem 217 00:09:42.810 --> 00:09:46.662 in New York was a huge hit with Japanese audiences. 218 00:09:46.662 --> 00:09:48.700 (woman screaming) 219 00:09:48.700 --> 00:09:51.930 - And so the comparison is not just a comparison 220 00:09:51.930 --> 00:09:54.350 evocative of power and strength, 221 00:09:54.350 --> 00:09:57.680 it's also kind of pointed squarely at New York City, 222 00:09:57.680 --> 00:10:00.544 and, therefore, pointed directly at the Americans. 223 00:10:00.544 --> 00:10:03.660 (soft music) (film whirs) 224 00:10:03.660 --> 00:10:07.250 - [Narrator] In March 1938, construction of Musashi 225 00:10:07.250 --> 00:10:11.243 began here at the Mitsubishi Shipyard in Nagasaki. 226 00:10:14.060 --> 00:10:17.470 Incredibly, the giant gantry crane that built her 227 00:10:17.470 --> 00:10:19.123 is still in use today. 228 00:10:21.560 --> 00:10:24.100 - The Japanese virtually had to reinvent 229 00:10:24.100 --> 00:10:26.700 naval architecture and design of ships 230 00:10:26.700 --> 00:10:29.143 to be able to build such colossal vessels. 231 00:10:30.730 --> 00:10:34.363 - [Narrator] Work proceeded under a literal veil of secrecy. 232 00:10:35.660 --> 00:10:37.500 - When they were being built, they were actually built 233 00:10:37.500 --> 00:10:39.120 behind gigantic curtains 234 00:10:39.120 --> 00:10:40.410 that were raised up in the shipyards. 235 00:10:40.410 --> 00:10:42.740 And so even friendly people couldn't see 236 00:10:42.740 --> 00:10:43.930 what was going on behind there. 237 00:10:43.930 --> 00:10:46.230 So there was some attempt to keep it a secret. 238 00:10:47.860 --> 00:10:49.700 - A schoolgirl at the time, 239 00:10:49.700 --> 00:10:52.253 Ms. Matsuura remember what it was like. 240 00:10:53.876 --> 00:10:55.010 (Sachie speaks in foreign language) 241 00:10:55.010 --> 00:10:56.330 - [Interpreter] I was told never to look 242 00:10:56.330 --> 00:10:58.350 in the direction of the shipyard, 243 00:10:58.350 --> 00:11:01.077 that soldiers are onboard keeping watch, 244 00:11:01.077 --> 00:11:05.030 "You must not look or the soldiers will take you away." 245 00:11:05.030 --> 00:11:06.960 Even as a child, I kind of sensed 246 00:11:06.960 --> 00:11:09.103 that a big war was going to break out. 247 00:11:09.946 --> 00:11:11.110 (dramatic music) 248 00:11:11.110 --> 00:11:16.110 - [Narrator] On December 7th, 1941, that war began. 249 00:11:16.180 --> 00:11:19.150 In it's surprise attack on Pearl Harbor, 250 00:11:19.150 --> 00:11:22.340 the Japanese Navy used carrier-based air power 251 00:11:22.340 --> 00:11:25.283 to devastating effect against the American fleet. 252 00:11:26.490 --> 00:11:30.450 Ironically, that success only reinforced it's faith 253 00:11:30.450 --> 00:11:33.023 in it's own new super battleships. 254 00:11:34.110 --> 00:11:36.040 - A lot of the naval theory at the time 255 00:11:36.040 --> 00:11:38.540 was based on this fleet-on-fleet engagement. 256 00:11:38.540 --> 00:11:40.390 The Japanese, in particular, were still hoping 257 00:11:40.390 --> 00:11:42.160 for that kind of thing. 258 00:11:42.160 --> 00:11:44.880 This is how you arrest sea control from the other guy, 259 00:11:44.880 --> 00:11:46.193 you defeat his fleet. 260 00:11:47.500 --> 00:11:48.880 (guns bang) 261 00:11:48.880 --> 00:11:53.020 - [Narrator] In August 1942, Musashi began 262 00:11:53.020 --> 00:11:54.990 secret sea trials. 263 00:11:54.990 --> 00:11:58.320 Weapons and defenses carefully kept out of sight 264 00:11:58.320 --> 00:12:01.253 from enemy spies were put to the test. 265 00:12:02.779 --> 00:12:04.950 - Mushashi's main armament came in the form 266 00:12:04.950 --> 00:12:09.950 of three turrets mounting three Type 94 naval guns. 267 00:12:10.060 --> 00:12:12.070 These were of 18-inch caliber, 268 00:12:12.070 --> 00:12:15.500 and were therefore the largest naval guns in use 269 00:12:15.500 --> 00:12:16.997 anywhere in the world. 270 00:12:16.997 --> 00:12:19.580 (guns banging) 271 00:12:22.550 --> 00:12:25.280 - [Narrator] To defend herself, Musashi was shielded 272 00:12:25.280 --> 00:12:29.370 by the heaviest armor ever used on a ships hull. 273 00:12:29.370 --> 00:12:32.900 The high-grade steel came from low-phosphorous iron 274 00:12:32.900 --> 00:12:36.513 secretly mined in Japanese occupied Manchuria. 275 00:12:38.070 --> 00:12:41.040 For 19-year-old Masahiro Ohishi 276 00:12:41.040 --> 00:12:42.790 and the hundreds of young sailors 277 00:12:42.790 --> 00:12:45.520 assigned to serve aboard this giant, 278 00:12:45.520 --> 00:12:49.174 Musashi was a technological wonder. 279 00:12:49.174 --> 00:12:53.120 (Masahiro speaks in foreign language) 280 00:12:53.120 --> 00:12:54.950 - [Interpreter] We never thought for a second 281 00:12:54.950 --> 00:12:58.280 that Musashi would sink and people would die. 282 00:12:58.280 --> 00:13:01.894 We believed that such a giant ship could not be taken down. 283 00:13:01.894 --> 00:13:03.920 (soft music) 284 00:13:03.920 --> 00:13:07.373 - [Narrator] To them, she was the King Kong of the sea. 285 00:13:11.448 --> 00:13:13.350 (dramatic music) 286 00:13:13.350 --> 00:13:16.140 Day 14 of the Musashi search expedition. 287 00:13:16.140 --> 00:13:18.280 - Five, in this direction here. 288 00:13:18.280 --> 00:13:20.110 - [Narrator] At last, the team thinks 289 00:13:20.110 --> 00:13:21.263 they're onto something. 290 00:13:22.431 --> 00:13:26.387 - [Man] It should be broken in four pieces sitting there. 291 00:13:26.387 --> 00:13:28.660 - [Narrator] One of their sonar runs 292 00:13:28.660 --> 00:13:31.528 has revealed a promising target. 293 00:13:31.528 --> 00:13:33.780 - [David] That is exactly what you wanna look for, 294 00:13:33.780 --> 00:13:37.652 bow, superstructure, things falling off the superstructure, 295 00:13:37.652 --> 00:13:40.840 blah, blah, blah, central area, engine room, 296 00:13:40.840 --> 00:13:43.261 break here, explosion there, stern. 297 00:13:43.261 --> 00:13:45.300 It's all gonna be right there. 298 00:13:45.300 --> 00:13:48.253 And if it capsized, it's gonna be over. 299 00:13:50.810 --> 00:13:53.950 - [Narrator] But after making several more sonar runs, 300 00:13:53.950 --> 00:13:56.690 they reluctantly reach the conclusion, 301 00:13:56.690 --> 00:13:58.773 the object is too large. 302 00:13:59.990 --> 00:14:01.530 - [David] You know, it's 100 meters bigger 303 00:14:01.530 --> 00:14:05.183 than what we're looking for, so it's 30% bigger. 304 00:14:05.183 --> 00:14:07.190 - [Rob] I think it's definitely something 305 00:14:08.180 --> 00:14:11.685 other than geology, but I don't think it's Musashi. 306 00:14:11.685 --> 00:14:14.185 (light music) 307 00:14:16.680 --> 00:14:17.990 - [Narrator] After three weeks, 308 00:14:17.990 --> 00:14:20.580 the expedition is out of time. 309 00:14:20.580 --> 00:14:23.197 The research vessel must return to port. 310 00:14:23.197 --> 00:14:27.221 But they've covered a staggering 1,400 square miles, 311 00:14:27.221 --> 00:14:30.740 an area as big as the state of Rhode Island. 312 00:14:30.740 --> 00:14:33.566 - What we now have is a very highly accurate map 313 00:14:33.566 --> 00:14:37.020 of the entire area that we want to search. 314 00:14:37.020 --> 00:14:38.810 We know where she's not, we've ruled out 315 00:14:38.810 --> 00:14:40.763 large swaths of the Sibuyan Sea. 316 00:14:41.640 --> 00:14:43.960 - [Narrator] And their commitment to the task 317 00:14:43.960 --> 00:14:46.290 has only intensified. 318 00:14:46.290 --> 00:14:48.340 - Everybody's kinda got a lot of blood, sweat and tears 319 00:14:48.340 --> 00:14:50.580 in trying to find this wreck. 320 00:14:50.580 --> 00:14:52.510 You know, you get this personal passion going 321 00:14:52.510 --> 00:14:54.381 trying to find this thing. 322 00:14:54.381 --> 00:14:56.320 (dramatic music) 323 00:14:56.320 --> 00:14:59.090 - [Narrator] But to succeed, they must first find 324 00:14:59.090 --> 00:15:02.877 a better tool for searching the rugged sea floor below. 325 00:15:02.877 --> 00:15:04.401 (water splashing) 326 00:15:04.401 --> 00:15:07.150 (dramatic music) 327 00:15:07.150 --> 00:15:10.270 By the time Musashi joined the Japanese war effort 328 00:15:10.270 --> 00:15:15.270 in the Pacific in 1942, the momentum was about to shift. 329 00:15:16.370 --> 00:15:18.160 - The Japanese, actually, are prevailing at this point, 330 00:15:18.160 --> 00:15:20.350 'cause they're better at surface warfare than we are 331 00:15:20.350 --> 00:15:22.300 at this early stage in the game. 332 00:15:22.300 --> 00:15:23.350 What then becomes clear 333 00:15:23.350 --> 00:15:26.350 is that anytime aircraft carriers get involved, 334 00:15:26.350 --> 00:15:28.300 the whole thing changes. 335 00:15:28.300 --> 00:15:30.230 - The US embraces naval airpower 336 00:15:30.230 --> 00:15:31.911 in a way that it just hadn't before. 337 00:15:31.911 --> 00:15:36.080 It revises the way that it trains, revises tactics 338 00:15:36.080 --> 00:15:38.280 and it revises weapons to the extent 339 00:15:38.280 --> 00:15:40.350 that it introduces a new fighter, 340 00:15:40.350 --> 00:15:42.990 a new dive bomber, a new torpedo bomber, 341 00:15:42.990 --> 00:15:45.993 and it even introduces a new torpedo. 342 00:15:46.860 --> 00:15:50.340 - [Narrator] The Mark 13 torpedo was more reliable 343 00:15:50.340 --> 00:15:52.140 and could be dropped at higher altitude 344 00:15:52.140 --> 00:15:53.353 than it's predecessor. 345 00:15:55.780 --> 00:15:58.960 At the same time, American intelligence 346 00:15:58.960 --> 00:16:01.490 secured a valuable lead. 347 00:16:01.490 --> 00:16:04.772 - On the island of Tulagi, Americans captured a document 348 00:16:04.772 --> 00:16:09.010 that was a warship recognition manual 349 00:16:09.010 --> 00:16:11.770 that was to be used by Imperial Navy sailors 350 00:16:11.770 --> 00:16:13.540 to recognize their own ships. 351 00:16:13.540 --> 00:16:17.543 And it had a drawing of a Yamato-class ship. 352 00:16:19.060 --> 00:16:21.313 - [Narrator] But after that, nothing. 353 00:16:22.680 --> 00:16:27.570 It's as if Japan's most secret weapon had vanished. 354 00:16:27.570 --> 00:16:30.350 - You'll find in the summer of 1944, 355 00:16:30.350 --> 00:16:33.550 the naval intelligence experts groping 356 00:16:33.550 --> 00:16:36.201 for an understanding of these huge ships 357 00:16:36.201 --> 00:16:41.201 and they came up with estimates that were just unbelievable. 358 00:16:42.180 --> 00:16:44.140 - [Narrator] But as they would later discover, 359 00:16:44.140 --> 00:16:48.001 even those estimates were way too small. 360 00:16:48.001 --> 00:16:50.090 (dramatic music) 361 00:16:50.090 --> 00:16:54.290 By June 1944, American forces succeeded 362 00:16:54.290 --> 00:16:56.590 in pushing the Japanese fleet, 363 00:16:56.590 --> 00:17:00.280 totalling some 60 ships and 450 aircraft, 364 00:17:00.280 --> 00:17:02.240 out of the Western Pacific. 365 00:17:02.240 --> 00:17:07.120 The battle became known as the Great Marianas Turkey Shoot. 366 00:17:07.120 --> 00:17:09.710 - They call it that because they harvest 367 00:17:09.710 --> 00:17:11.710 so many Japanese aircraft. 368 00:17:11.710 --> 00:17:14.420 They shoot them down wholesale. 369 00:17:14.420 --> 00:17:16.800 The Japanese lose half their carrier strength 370 00:17:16.800 --> 00:17:21.303 and they lose almost all of their naval aviation. 371 00:17:22.390 --> 00:17:24.810 - [Narrator] American general Douglas MacArthur 372 00:17:24.810 --> 00:17:27.280 was now poised to invade the gateway 373 00:17:27.280 --> 00:17:30.563 to Japan itself, the Philippines. 374 00:17:32.936 --> 00:17:36.260 On October 20th, MacArthur came ashore 375 00:17:36.260 --> 00:17:39.530 on the eastern side of Leyte Island, 376 00:17:39.530 --> 00:17:42.643 where American troops encountered little resistance. 377 00:17:43.950 --> 00:17:48.950 - The opinion, united, of American intelligence agencies 378 00:17:48.990 --> 00:17:51.930 was that the Japanese Navy would not come out. 379 00:17:51.930 --> 00:17:55.180 We based our ideas on the assumption 380 00:17:55.180 --> 00:17:58.220 that the Japanese would need a considerable amount of time 381 00:17:58.220 --> 00:18:01.220 to train new aircrew and pilots 382 00:18:01.220 --> 00:18:03.253 for their aircraft carrier groups. 383 00:18:05.150 --> 00:18:07.440 - [Narrator] But American intelligence was ignoring 384 00:18:07.440 --> 00:18:11.910 one critical fact: Japan's Navy remained committed 385 00:18:11.910 --> 00:18:14.573 to fighting a decisive battle at sea. 386 00:18:15.510 --> 00:18:18.780 It's surface fleet was still largely intact, 387 00:18:18.780 --> 00:18:22.483 led by two giants Americans had yet to lay eyes on, 388 00:18:23.340 --> 00:18:25.363 Musashi and Yamato. 389 00:18:26.200 --> 00:18:28.970 - American radio intelligence had knowledge 390 00:18:28.970 --> 00:18:31.392 of the movements of these Japanese ships, 391 00:18:31.392 --> 00:18:35.920 but still not of their characteristics. 392 00:18:35.920 --> 00:18:39.050 - [Narrator] On October 24th, 1944, 393 00:18:39.050 --> 00:18:42.600 Admiral Kurita's Center Force, with 26 ships, 394 00:18:42.600 --> 00:18:44.273 entered the Sibuyan Sea. 395 00:18:45.570 --> 00:18:48.220 Two other slightly smaller Japanese fleets 396 00:18:48.220 --> 00:18:50.343 approached from the south and north. 397 00:18:51.740 --> 00:18:54.964 The Battle of Leyte Gulf was about to begin. 398 00:18:54.964 --> 00:18:58.280 (soft dramatic music) 399 00:18:58.280 --> 00:19:01.960 - In the morning, when Kurita is crossing the Sibuyan Sea, 400 00:19:01.960 --> 00:19:03.890 the reconnaissance flights picked this up, 401 00:19:03.890 --> 00:19:05.430 and, of course, at that point, they're aware 402 00:19:05.430 --> 00:19:08.810 they got two very large battleships down here. 403 00:19:08.810 --> 00:19:10.585 - [Narrator] American Pilots were the first 404 00:19:10.585 --> 00:19:14.663 to catch a real glimpse of Musashi and Yamato. 405 00:19:15.540 --> 00:19:18.327 - We knew that they had two big battleships, 406 00:19:18.327 --> 00:19:19.893 and that's about all we knew. 407 00:19:21.020 --> 00:19:23.833 And it was, obviously, the biggest thing we'd ever seen. 408 00:19:24.900 --> 00:19:27.020 - [Narrator] Although caught by surprise, 409 00:19:27.020 --> 00:19:29.770 the US Navy was prepared. 410 00:19:29.770 --> 00:19:33.680 7th Fleet moved to guard the Leyte landing site itself, 411 00:19:33.680 --> 00:19:37.263 while 3rd Fleet deployed in three groups to the north. 412 00:19:38.220 --> 00:19:40.520 - Unfortunately, the one element of the 3rd Fleet 413 00:19:40.520 --> 00:19:42.256 that's closest to San Bernardino Strait 414 00:19:42.256 --> 00:19:44.370 is a little bit weaker because it sent 415 00:19:44.370 --> 00:19:46.413 one of it's carriers off to refuel. 416 00:19:47.430 --> 00:19:50.831 It's sole remaining large carrier was only half the size 417 00:19:50.831 --> 00:19:54.240 of the two giants bearing down on it 418 00:19:54.240 --> 00:19:58.393 with 24 more warships in Japan's Center Force. 419 00:19:59.957 --> 00:20:02.705 (soft dramatic music) 420 00:20:02.705 --> 00:20:05.610 (man speaking faintly on radio) 421 00:20:05.610 --> 00:20:08.460 - [Narrator] In late February 2015, 422 00:20:08.460 --> 00:20:12.533 Rob Kraft and David Mearns renew their search for Musashi. 423 00:20:14.290 --> 00:20:15.970 Since they were last here, 424 00:20:15.970 --> 00:20:19.373 they've found the perfect tool for the difficult task ahead. 425 00:20:22.410 --> 00:20:25.803 It's now installed aboard the expedition yacht, Octopus, 426 00:20:27.090 --> 00:20:30.053 equipped with state-of-the-art deep sea equipment. 427 00:20:32.720 --> 00:20:35.910 Their key search tool is still so new, 428 00:20:35.910 --> 00:20:39.104 it's rarely been used in the deep ocean. 429 00:20:39.104 --> 00:20:40.370 (machine whirs) 430 00:20:40.370 --> 00:20:43.790 - AUV is an autonomous underwater vehicle. 431 00:20:43.790 --> 00:20:48.163 Our AUV is capable of diving down to 1,500 meters. 432 00:20:49.280 --> 00:20:51.930 It takes with it a side scan sonar system 433 00:20:51.930 --> 00:20:56.450 that looks out on the sides and provides us an image 434 00:20:56.450 --> 00:20:58.683 of things that may be lying on he seafloor. 435 00:20:59.980 --> 00:21:02.420 - [Narrator] It's survey route is selected based on 436 00:21:02.420 --> 00:21:05.950 the bathymetric map that system engineer Wayne Szydtowski 437 00:21:05.950 --> 00:21:09.103 compiled during the 2011 expedition. 438 00:21:10.400 --> 00:21:13.340 - This map is of the, basically, of the sub sea volcano 439 00:21:13.340 --> 00:21:14.280 that we're seeing. 440 00:21:14.280 --> 00:21:15.740 And so, using this map, 441 00:21:15.740 --> 00:21:18.103 we then program the autonomous vehicle. 442 00:21:19.382 --> 00:21:21.960 - [Narrator] Traveling 2/3 of a mile down 443 00:21:21.960 --> 00:21:24.910 and a few hundred feet above the ocean floor, 444 00:21:24.910 --> 00:21:27.023 the AUV maps the terrain. 445 00:21:28.060 --> 00:21:30.170 But distinguishing a man-made object 446 00:21:30.170 --> 00:21:33.780 among the rugged volcanic outcrops is challenging. 447 00:21:33.780 --> 00:21:35.810 - Because a lava rock is as reflective 448 00:21:35.810 --> 00:21:37.810 as the acoustic waves are that we use 449 00:21:37.810 --> 00:21:40.073 to bounce off the metal of the Musashi. 450 00:21:41.880 --> 00:21:45.410 - [Narrator] After 18 hours, the AUV returns to the surface 451 00:21:45.410 --> 00:21:47.923 and is brought onboard to download the data. 452 00:21:49.680 --> 00:21:53.250 - Everybody had a go at looking at this HYSCAN information. 453 00:21:53.250 --> 00:21:54.770 Everybody, what do you see? 454 00:21:54.770 --> 00:21:55.810 Oh, that's something shiny there. 455 00:21:55.810 --> 00:21:57.540 That's a rock, no that's a rock. 456 00:21:57.540 --> 00:21:58.710 No, that's something. 457 00:21:58.710 --> 00:21:59.610 No, that's a rock. 458 00:22:00.500 --> 00:22:03.263 - [Narrator] The first AUV survey yields nothing, 459 00:22:04.760 --> 00:22:05.923 as does the second. 460 00:22:07.080 --> 00:22:09.360 - And I'll tell you that, up to that point, 461 00:22:09.360 --> 00:22:11.970 we were starting to second-guess ourselves. 462 00:22:11.970 --> 00:22:16.340 We had searched a large portion of the primary search area. 463 00:22:16.340 --> 00:22:19.453 And we weren't finding what we had hoped to find. 464 00:22:22.070 --> 00:22:25.972 - [Narrator] On the third run, they finally see something. 465 00:22:25.972 --> 00:22:28.410 (water gurgling) 466 00:22:28.410 --> 00:22:30.580 - Generally, when you're finding a wreck, 467 00:22:30.580 --> 00:22:33.110 it's either happening instantaneously, 468 00:22:33.110 --> 00:22:35.650 but, in this one, it was a bit of a slow burner, 469 00:22:35.650 --> 00:22:38.767 because there sonar image didn't sort of shout out, 470 00:22:38.767 --> 00:22:40.990 "This is Musashi, this is where I sank." 471 00:22:40.990 --> 00:22:44.300 it was more of there was an indication something was there. 472 00:22:44.300 --> 00:22:46.194 - [Man] David, buoy in the water. 473 00:22:46.194 --> 00:22:47.354 That's a safe heading 474 00:22:47.354 --> 00:22:49.150 Better wench that one up. 475 00:22:49.150 --> 00:22:51.120 - [Narrator] For a closer look, they launch 476 00:22:51.120 --> 00:22:53.713 a remotely operated vehicle, or ROV. 477 00:22:54.900 --> 00:22:57.050 - It's smaller than a Volkswagen Bug, 478 00:22:57.050 --> 00:22:59.020 but it's still quite substantial. 479 00:22:59.020 --> 00:23:01.530 And it's on a cable as well, but in that cable 480 00:23:01.530 --> 00:23:04.062 it has power conductors and fiber, 481 00:23:04.062 --> 00:23:05.930 and through that, we get to watch 482 00:23:05.930 --> 00:23:08.483 our HD camera that's on the end of a tether. 483 00:23:09.830 --> 00:23:11.550 - [Narrator] It will take the ROV an hour 484 00:23:11.550 --> 00:23:15.083 to reach the ocean floor almost a mile below, 485 00:23:17.110 --> 00:23:20.050 plenty of time to wonder if, at last, 486 00:23:20.050 --> 00:23:22.694 they're going to set eyes on Musashi. 487 00:23:22.694 --> 00:23:25.840 (dramatic music) 488 00:23:25.840 --> 00:23:29.800 On the morning of October 24th, 1944, 489 00:23:29.800 --> 00:23:32.320 the skies over the Sibuyan Sea were filled 490 00:23:32.320 --> 00:23:34.713 with over 40 American warplanes. 491 00:23:36.680 --> 00:23:40.330 - US Naval aircraft that opposed the Japanese Center Force 492 00:23:40.330 --> 00:23:44.367 in the Sibuyan Sea consists of the Hellcat fighter, 493 00:23:44.367 --> 00:23:49.350 the Helldiver dive bomber, and the Avenger torpedo bomber. 494 00:23:49.350 --> 00:23:52.390 - [Narrator] The fighters led the way with strafing runs. 495 00:23:52.390 --> 00:23:53.850 - You're gonna go after the battleships 496 00:23:53.850 --> 00:23:56.220 because they are the biggest target. 497 00:23:56.220 --> 00:23:57.700 They can do the most damage to you, 498 00:23:57.700 --> 00:23:59.800 and, therefore, you want to take them out. 499 00:24:00.710 --> 00:24:02.916 - [Narrator] But the Japanese gunners were ready, 500 00:24:02.916 --> 00:24:04.800 (plane engines roars) 501 00:24:04.800 --> 00:24:06.310 unleashing a hail of fire 502 00:24:06.310 --> 00:24:09.543 from Mushashi's 100 anti-aircraft guns. 503 00:24:10.746 --> 00:24:13.329 (guns banging) 504 00:24:18.730 --> 00:24:20.310 (Akio speaks in foreign language) 505 00:24:20.310 --> 00:24:22.710 - [Interpreter] Aerial attacks had become fierce 506 00:24:22.710 --> 00:24:24.600 after war broke out. 507 00:24:24.600 --> 00:24:26.050 So the decision was made 508 00:24:26.050 --> 00:24:28.660 to strengthen anti-aircraft defenses, 509 00:24:28.660 --> 00:24:32.080 and machine guns were also rapidly added. 510 00:24:32.080 --> 00:24:34.270 But there was no industrial capacity 511 00:24:34.270 --> 00:24:37.253 to manufacture bullet-proof armor at this point. 512 00:24:39.100 --> 00:24:40.790 - [Narrator] With little to protect them, 513 00:24:40.790 --> 00:24:43.743 some of the gun crews suffered heavy casualties. 514 00:24:44.986 --> 00:24:48.510 (Yoshiaki speaks in foreign language) 515 00:24:48.510 --> 00:24:50.860 - [Interpreter] Everything was blown to bits. 516 00:24:50.860 --> 00:24:53.360 There were pieces of machine gun everywhere 517 00:24:53.360 --> 00:24:55.740 with human flesh stuck to them. 518 00:24:55.740 --> 00:24:58.590 I could not believe that they were parts of human beings. 519 00:25:00.140 --> 00:25:02.850 - [Narrator] Bob Freligh was a 22-year-old pilot 520 00:25:02.850 --> 00:25:05.603 flying an Avenger torpedo bomber that day. 521 00:25:06.570 --> 00:25:09.660 - The sky is so big up there, I don't see all the fighters. 522 00:25:09.660 --> 00:25:12.500 I don't have time to look around to see anybody else 523 00:25:12.500 --> 00:25:14.533 because everything happens like that. 524 00:25:15.710 --> 00:25:19.683 - [Narrator] What he did see was a giant battleships below. 525 00:25:20.570 --> 00:25:24.300 - The Musashi has 11 planes coming in on it. 526 00:25:24.300 --> 00:25:27.900 You're coming down and you start leveling off. 527 00:25:27.900 --> 00:25:29.980 And all this time, they're shooting at you 528 00:25:29.980 --> 00:25:32.830 and you don't know whether this bullets gonna hit you or. 529 00:25:34.240 --> 00:25:38.310 So you get about the distance that you think you should be, 530 00:25:38.310 --> 00:25:42.250 at the altitude you should be, open your bomb bay doors, 531 00:25:42.250 --> 00:25:43.812 and you're all set, boom. 532 00:25:43.812 --> 00:25:45.090 (plane engine roars) 533 00:25:45.090 --> 00:25:46.700 - [Narrator] His rear gunner watched 534 00:25:46.700 --> 00:25:49.360 as their 2,000 pound torpedo slammed 535 00:25:49.360 --> 00:25:51.289 into Mushashi's port side. 536 00:25:51.289 --> 00:25:52.810 (torpedo bangs) 537 00:25:52.810 --> 00:25:55.460 - The torpedo bomber is the most effective weapon 538 00:25:55.460 --> 00:25:58.280 against a battleships because it can release something 539 00:25:58.280 --> 00:26:00.230 that carries a great deal of punch. 540 00:26:00.230 --> 00:26:02.810 The American Mark 13 torpedo carried a warhead 541 00:26:02.810 --> 00:26:05.040 of 600 pounds of high explosive. 542 00:26:05.040 --> 00:26:09.247 That was enough force to punch through an armor belt. 543 00:26:09.247 --> 00:26:11.130 (dramatic music) 544 00:26:11.130 --> 00:26:12.980 - [Narrator] Musashi withstood the initial 545 00:26:12.980 --> 00:26:16.613 American assault, but the attacks kept coming. 546 00:26:16.613 --> 00:26:19.970 (torpedoes banging) 547 00:26:19.970 --> 00:26:22.200 - The fleets that are there at Leyte 548 00:26:22.200 --> 00:26:25.030 consist of multiple aircraft carriers. 549 00:26:25.030 --> 00:26:26.960 It's mind-boggling by today's standards 550 00:26:26.960 --> 00:26:28.550 how many ships were there. 551 00:26:28.550 --> 00:26:30.530 And so, as a result of that, they can continue 552 00:26:30.530 --> 00:26:33.683 to attack and attack, and wave after wave coming in. 553 00:26:34.928 --> 00:26:37.220 (torpedo bangs) 554 00:26:37.220 --> 00:26:40.070 - [Narrator] During the last wave, an American pilot 555 00:26:40.070 --> 00:26:42.464 took his memorable series of photographs. 556 00:26:42.464 --> 00:26:45.464 (flash bulb popping) 557 00:26:45.464 --> 00:26:47.220 (plane engines roar) 558 00:26:47.220 --> 00:26:51.170 - [Narrator] The relentless onslaught began to take a toll. 559 00:26:51.170 --> 00:26:55.110 - When the Musashi loses speed and falls behind, 560 00:26:55.110 --> 00:26:58.523 then it's obvious that she's damaged, 561 00:26:59.660 --> 00:27:03.693 so now's the moment to close in for the kill. 562 00:27:03.693 --> 00:27:05.500 (soft dramatic music) 563 00:27:05.500 --> 00:27:07.464 - [Narrator] Lionel Gilbow was the rear gunner 564 00:27:07.464 --> 00:27:08.724 in a Helldiver bomber. 565 00:27:08.724 --> 00:27:10.260 (plane whooshes) 566 00:27:10.260 --> 00:27:13.030 - I probably dived-bombed a battleship 567 00:27:13.030 --> 00:27:16.070 with a 2,000 pound armor piercing bomb, 568 00:27:16.070 --> 00:27:17.393 right down the stack. 569 00:27:18.470 --> 00:27:21.440 (torpedo bangs) 570 00:27:21.440 --> 00:27:24.300 - These particular ships are very formidable ships, 571 00:27:24.300 --> 00:27:26.410 but they also made very large targets 572 00:27:26.410 --> 00:27:27.810 that were easily identified. 573 00:27:27.810 --> 00:27:29.040 And I think that's one of the reasons 574 00:27:29.040 --> 00:27:32.310 a lot of the aviators concentrated on Musashi, 575 00:27:32.310 --> 00:27:34.163 and she paid the price as a result. 576 00:27:35.510 --> 00:27:38.130 - [Narrator] Yamato escaped the onslaught, 577 00:27:38.130 --> 00:27:43.053 but at 7:39 p.m., four hours after the final attack, 578 00:27:44.440 --> 00:27:49.210 Musashi, crippled, yet miraculously still in one piece, 579 00:27:49.210 --> 00:27:51.072 rolled over and sank. 580 00:27:51.072 --> 00:27:52.876 (propellers whirring) 581 00:27:52.876 --> 00:27:55.730 (Masahiro speaks in foreign language) 582 00:27:55.730 --> 00:27:57.920 - [Interpreter] Hundreds of people are crying for help 583 00:27:57.920 --> 00:28:01.453 in horrified voices, as they were all sucked into the waves. 584 00:28:02.514 --> 00:28:05.347 (water splashing) 585 00:28:09.869 --> 00:28:12.633 (metal creaks) 586 00:28:12.633 --> 00:28:15.050 (soft music) 587 00:28:17.180 --> 00:28:20.090 - [Narrator] In the pitch darkness of the deep sea, 588 00:28:20.090 --> 00:28:24.100 the ROV pilot carefully maneuvers his vehicle. 589 00:28:24.100 --> 00:28:27.510 - We came across some very small pieces of debris 590 00:28:27.510 --> 00:28:30.520 which looked the right age, looked the right material. 591 00:28:30.520 --> 00:28:32.580 But we weren't quite certain. 592 00:28:32.580 --> 00:28:35.130 - Everybody was pretty much running on adrenalin 593 00:28:35.130 --> 00:28:36.200 at that time. 594 00:28:36.200 --> 00:28:38.033 It was very exciting. 595 00:28:39.120 --> 00:28:40.910 - [Narrator] The ROV moves slowly 596 00:28:40.910 --> 00:28:43.133 through this unfamiliar landscape. 597 00:28:44.819 --> 00:28:47.650 - It took about, I guess, a half hour or 45 minutes 598 00:28:47.650 --> 00:28:50.230 before we started getting into the heavier debris. 599 00:28:50.230 --> 00:28:53.506 And then it became more and more obvious. 600 00:28:53.506 --> 00:28:55.100 - [Man] Look, you see them, right? 601 00:28:55.100 --> 00:28:57.950 There's three characters over there, I think. 602 00:28:57.950 --> 00:29:01.253 - [Man] That's Japanese, it's a Japanese warship. 603 00:29:02.300 --> 00:29:03.583 - The minute we found the valve 604 00:29:03.583 --> 00:29:06.440 that had the Kanji writing on it, it was like, 605 00:29:06.440 --> 00:29:09.000 okay, this is Japanese, now all we have to do 606 00:29:09.000 --> 00:29:10.350 is prove that it's Musashi. 607 00:29:12.900 --> 00:29:16.363 - [Narrator] To do that, they need to find the ship's bow. 608 00:29:17.820 --> 00:29:20.000 - [Man] There's the bollards, two bollards. 609 00:29:21.180 --> 00:29:22.480 So we're not too far away. 610 00:29:23.383 --> 00:29:25.730 It'll be above the degaussing cable. 611 00:29:28.963 --> 00:29:30.463 Something's there. 612 00:29:32.183 --> 00:29:33.100 It's there. 613 00:29:35.280 --> 00:29:37.710 - [Narrator] The gold paint is gone, 614 00:29:37.710 --> 00:29:41.460 but the outline of the imperial Japanese flower emblem 615 00:29:41.460 --> 00:29:42.743 is still there. 616 00:29:44.030 --> 00:29:47.840 - As soon as we found the chrysanthemum on the bow, 617 00:29:47.840 --> 00:29:49.443 we knew what we were looking at. 618 00:29:49.443 --> 00:29:53.040 - That's, that's proof positive. 619 00:29:53.040 --> 00:29:56.210 - It wasn't the kind of jumping up and shouting for joy 620 00:29:56.210 --> 00:29:58.530 that I've experienced in the past, 621 00:29:58.530 --> 00:30:01.920 it was a sort of a quiet relief. 622 00:30:01.920 --> 00:30:03.070 We had finally done it. 623 00:30:04.610 --> 00:30:07.970 - [Narrator] At long last, Musashi is found, 624 00:30:07.970 --> 00:30:10.930 but a new, and still more intriguing mystery 625 00:30:10.930 --> 00:30:12.403 is about to emerge. 626 00:30:14.027 --> 00:30:16.440 (soft music) 627 00:30:16.440 --> 00:30:19.630 Over the next week, the search team explores the wreck 628 00:30:19.630 --> 00:30:20.883 of the super battleship. 629 00:30:22.274 --> 00:30:23.874 - There's some shells on the top 630 00:30:25.812 --> 00:30:26.800 - [Rob] I think there's another one 631 00:30:26.800 --> 00:30:30.920 of the mounts for a light, or a-- 632 00:30:30.920 --> 00:30:33.480 - [Narrator] 70 years after she disappeared, 633 00:30:33.480 --> 00:30:36.050 they're compiling the first detailed picture 634 00:30:36.050 --> 00:30:38.463 of a lost technological marvel. 635 00:30:39.890 --> 00:30:41.740 - Because there are no drawings for this ship 636 00:30:41.740 --> 00:30:43.430 and there's only a handful of photographs, 637 00:30:43.430 --> 00:30:45.790 so we're the first people really 638 00:30:45.790 --> 00:30:47.573 to document what she looks like. 639 00:30:48.940 --> 00:30:52.007 - [Narrator] They also find signs of those who sailed her, 640 00:30:52.940 --> 00:30:55.223 a shoe, a helmet, 641 00:30:56.410 --> 00:30:59.175 and something unexpected on a warship. 642 00:30:59.175 --> 00:31:00.280 - [David] That's film. 643 00:31:00.280 --> 00:31:01.330 - [Woman] No, that's film. 644 00:31:01.330 --> 00:31:03.530 - [David] That is a film strip. 645 00:31:03.530 --> 00:31:05.760 It's not just a metal ship, these are crew 646 00:31:05.760 --> 00:31:06.840 that served in it, 647 00:31:06.840 --> 00:31:09.210 and some obviously died on the site as well, 648 00:31:09.210 --> 00:31:11.480 so it's important to document that. 649 00:31:15.250 --> 00:31:17.210 (soft dramatic music) 650 00:31:17.210 --> 00:31:19.240 - [Narrator] Musashi lies a good distance 651 00:31:19.240 --> 00:31:21.180 from the sinking position reported 652 00:31:21.180 --> 00:31:22.553 by the destroyer Kiyoshimo. 653 00:31:24.270 --> 00:31:26.510 (flash bulb pops) 654 00:31:26.510 --> 00:31:29.743 But that's not the only reason she was so hard to find. 655 00:31:31.220 --> 00:31:34.160 - The Musashi is literally on the side of a volcano. 656 00:31:34.160 --> 00:31:36.000 And if you've hiked up a volcano before, 657 00:31:36.000 --> 00:31:38.480 you'd know there's great big huge rocks and outcroppings 658 00:31:38.480 --> 00:31:42.443 and boulders, and so it's hidden inside the geology. 659 00:31:44.420 --> 00:31:47.090 - [Narrator] The difficulty in finding the wreck 660 00:31:47.090 --> 00:31:49.903 is also explained by her shocking condition. 661 00:31:52.560 --> 00:31:54.708 - Just the complete and utter destruction 662 00:31:54.708 --> 00:31:59.020 of the ship itself, the stern and the bow sections 663 00:31:59.020 --> 00:32:02.053 are really the only whole parts of the hull that remain. 664 00:32:02.900 --> 00:32:06.670 The bridge is somewhat intact from what we can see, 665 00:32:06.670 --> 00:32:08.840 but the rest, you know, the center section of the ship 666 00:32:08.840 --> 00:32:10.733 was just completely destroyed. 667 00:32:12.590 --> 00:32:15.430 - So, essentially, it's broken it's back 668 00:32:15.430 --> 00:32:17.730 in at least two different locations. 669 00:32:17.730 --> 00:32:21.480 And for a ship that withstood so many attacks 670 00:32:21.480 --> 00:32:26.000 from torpedoes and bombs and essentially sank intact, 671 00:32:26.000 --> 00:32:27.493 that's more than I expected. 672 00:32:28.680 --> 00:32:30.230 - [Narrator] What then could have caused 673 00:32:30.230 --> 00:32:32.159 such widespread destruction? 674 00:32:32.159 --> 00:32:33.510 (graphics whirring) 675 00:32:33.510 --> 00:32:36.313 It's a question which, so far, has no answer. 676 00:32:37.788 --> 00:32:39.083 (dramatic music) 677 00:32:39.083 --> 00:32:40.140 (guns bang) 678 00:32:40.140 --> 00:32:42.940 One of the last pieces to be discovered 679 00:32:42.940 --> 00:32:45.453 is Musashi's most potent weapon. 680 00:32:46.395 --> 00:32:48.900 (guns banging) 681 00:32:48.900 --> 00:32:52.290 - Which is, obviously, what caught everybody's imagination, 682 00:32:52.290 --> 00:32:55.110 these special 18-inch guns. 683 00:32:55.110 --> 00:32:57.400 These guns are held into the body of the ship, 684 00:32:57.400 --> 00:32:59.420 into the barbettes by gravity alone. 685 00:32:59.420 --> 00:33:03.330 So when the ship capsizes, they're incredibly heavy objects 686 00:33:03.330 --> 00:33:05.430 that just fall out under their own weight. 687 00:33:06.590 --> 00:33:09.253 We found one of these guns after a week of searching. 688 00:33:10.590 --> 00:33:13.010 - [Narrator] By now, the expedition has assembled 689 00:33:13.010 --> 00:33:15.223 an extensive record of Musashi, 690 00:33:16.260 --> 00:33:19.093 over 100 hours of video footage alone. 691 00:33:21.480 --> 00:33:24.210 - We want to make sure that we have fully documented 692 00:33:24.210 --> 00:33:25.910 the condition and the state of the wreck 693 00:33:25.910 --> 00:33:28.210 so we can share that with everybody and, you know, 694 00:33:28.210 --> 00:33:30.380 what we've done here and the data that we've gathered. 695 00:33:30.380 --> 00:33:32.542 We'll provide the clues that people can use 696 00:33:32.542 --> 00:33:35.230 to recreate or have an understanding 697 00:33:35.230 --> 00:33:37.308 of what actually happened. 698 00:33:37.308 --> 00:33:39.820 (light music) 699 00:33:39.820 --> 00:33:42.810 - [Narrator] The search team has opened a door. 700 00:33:42.810 --> 00:33:47.383 Now, others must step in to unravel Musashi's final hours. 701 00:33:49.430 --> 00:33:53.750 In March 2016, a group of Japanese experts assembles 702 00:33:53.750 --> 00:33:56.073 in Tokyo to take up the challenge. 703 00:33:58.270 --> 00:34:01.040 (soft dramatic music) 704 00:34:01.040 --> 00:34:05.110 To help them, the Japanese broadcaster, NHK, 705 00:34:05.110 --> 00:34:07.173 has created a valuable tool. 706 00:34:08.160 --> 00:34:11.630 Like pieces of a gigantic puzzle, it's taken the hours 707 00:34:11.630 --> 00:34:14.573 of digital images gathered by the search expedition, 708 00:34:15.740 --> 00:34:18.293 painstakingly piecing them back together, 709 00:34:19.660 --> 00:34:22.673 and creating a unique 3D model of the wreck. 710 00:34:25.635 --> 00:34:28.635 (graphics whirring) 711 00:34:42.300 --> 00:34:46.470 Only now is Musashi's enormous size apparent. 712 00:34:46.470 --> 00:34:50.610 At 263 meters, some 900 feet, 713 00:34:50.610 --> 00:34:53.193 she's longer than three jumbo jets. 714 00:34:55.165 --> 00:34:59.415 (men speaking in foreign language) 715 00:35:01.180 --> 00:35:04.250 To begin with, these experts want to find out 716 00:35:04.250 --> 00:35:07.340 why a ship so many believed unsinkable 717 00:35:07.340 --> 00:35:10.039 should fail it's first serious test. 718 00:35:10.039 --> 00:35:11.992 (Masami speaks in foreign language) 719 00:35:11.992 --> 00:35:14.230 (man speaks in foreign language) 720 00:35:14.230 --> 00:35:17.370 - [Interpreter] What is that thing that looks like a hole? 721 00:35:17.370 --> 00:35:20.070 - [Narrator] Masami Tezuka has been studying the Musashi 722 00:35:20.070 --> 00:35:21.333 for 30 years. 723 00:35:22.920 --> 00:35:24.963 He believes he's identified one clue, 724 00:35:26.030 --> 00:35:29.480 a damaged section protruding from the port bow, 725 00:35:29.480 --> 00:35:32.934 most likely caused by a torpedo strike. 726 00:35:32.934 --> 00:35:36.530 (Masami speaks in foreign language) 727 00:35:36.530 --> 00:35:38.370 - [Interpreter] Musashi would lose speed as a result, 728 00:35:38.370 --> 00:35:40.840 making it difficult to steer her. 729 00:35:40.840 --> 00:35:42.220 From an attackers point of view, 730 00:35:42.220 --> 00:35:44.390 a battleship that's dragging swuld have been easier to hit 731 00:35:44.390 --> 00:35:45.813 with bombs or torpedoes. 732 00:35:47.980 --> 00:35:49.650 - [Narrator] The last photo of Musashi 733 00:35:49.650 --> 00:35:53.270 shows her down at the bow, leading to the belief 734 00:35:53.270 --> 00:35:55.763 that flooding here caused her to sink. 735 00:35:57.511 --> 00:35:59.790 But a new scientific investigation 736 00:36:00.660 --> 00:36:04.513 at the University of Kobe tells a different story. 737 00:36:06.100 --> 00:36:09.570 Professor Hirotada Hashimoto, a specialist 738 00:36:09.570 --> 00:36:12.563 in naval architecture, conducted the analysis. 739 00:36:13.650 --> 00:36:16.750 When he simulates flooding inside the bow, 740 00:36:16.750 --> 00:36:18.570 the ship does pitch forward. 741 00:36:20.030 --> 00:36:22.770 But results show, water-tight compartments 742 00:36:22.770 --> 00:36:25.873 in the rest of the ship would not have been affected. 743 00:36:26.901 --> 00:36:29.610 (Hirotada speaks in foreign language) 744 00:36:29.610 --> 00:36:31.010 - [Interpreter] Even if the bow, 745 00:36:31.010 --> 00:36:33.740 including the part protected by armored plating, 746 00:36:33.740 --> 00:36:35.750 is completely filled with water, 747 00:36:35.750 --> 00:36:38.740 the ship will still be left with enough buoyancy. 748 00:36:38.740 --> 00:36:41.670 So this flooding alone definitely could not have caused 749 00:36:41.670 --> 00:36:43.873 the ship to sink or capsize. 750 00:36:45.560 --> 00:36:48.650 - [Narrator] To find answers to why Musashi sank, 751 00:36:48.650 --> 00:36:51.681 these experts will have to look elsewhere, 752 00:36:51.681 --> 00:36:55.833 starting in the place where Musashi was constructed. 753 00:36:57.443 --> 00:36:59.940 (soft music) 754 00:36:59.940 --> 00:37:03.050 At the Mitsubishi shipyard in Nagasaki, 755 00:37:03.050 --> 00:37:05.833 the Japanese team makes an important discovery. 756 00:37:07.350 --> 00:37:11.613 A file marked Musashi is uncovered in the company archives. 757 00:37:13.750 --> 00:37:16.200 It contains more than 200 pages 758 00:37:16.200 --> 00:37:19.123 of never-before released original blueprints. 759 00:37:24.400 --> 00:37:26.940 - [Narrator] By comparing images of the scattered pieces 760 00:37:26.940 --> 00:37:29.440 of the wreck with the blueprint, 761 00:37:29.440 --> 00:37:31.663 the team is able to identify them. 762 00:37:32.526 --> 00:37:36.110 (men speaking in foreign language) 763 00:37:36.110 --> 00:37:41.110 A pump, a boiler, all parts protected 764 00:37:41.290 --> 00:37:42.940 by the heavy steel armor 765 00:37:42.940 --> 00:37:45.433 intended to make Musashi unsinkable. 766 00:37:46.660 --> 00:37:47.493 (Akio speaks in foreign language) 767 00:37:47.493 --> 00:37:49.240 - [Interpreter] So the biggest question is 768 00:37:49.240 --> 00:37:50.833 where did the armor go? 769 00:37:52.160 --> 00:37:54.230 - [Narrator] In the high-resolution sonar image 770 00:37:54.230 --> 00:37:58.810 of the debris field, one structure attracts their attention. 771 00:37:58.810 --> 00:38:01.580 Examining video footage from the area, 772 00:38:01.580 --> 00:38:05.040 they discover a 90-foot piece of steel. 773 00:38:05.040 --> 00:38:07.757 It looks like part of the missing armor. 774 00:38:07.757 --> 00:38:09.440 (graphics whirring) 775 00:38:09.440 --> 00:38:11.880 When they match it up to the 3D model, 776 00:38:11.880 --> 00:38:15.013 they find it comes from the hull on the port side. 777 00:38:16.460 --> 00:38:18.093 But how did it come loose? 778 00:38:20.103 --> 00:38:22.190 - Musashi's armor belt was so thick, 779 00:38:22.190 --> 00:38:24.890 that everyone felt very confident onboard the ship, 780 00:38:24.890 --> 00:38:26.520 that they could stand up to the punishment 781 00:38:26.520 --> 00:38:28.440 of any weapon that could be thrown at it. 782 00:38:28.440 --> 00:38:31.983 But, whereas ships making use of a thinner plate 783 00:38:31.983 --> 00:38:35.450 that could be welded, Musashi's armor could not be welded. 784 00:38:35.450 --> 00:38:36.570 It was simply too thick. 785 00:38:36.570 --> 00:38:38.270 And so they turned back their the 19th century 786 00:38:38.270 --> 00:38:41.023 and simply hot riveted the plates together. 787 00:38:42.580 --> 00:38:44.070 - [Narrator] A company that took part 788 00:38:44.070 --> 00:38:46.620 in riveting the armor for Musashi 789 00:38:46.620 --> 00:38:48.633 is still operating in Osaka. 790 00:38:49.540 --> 00:38:53.373 Two workers recreate the technique used at the time 791 00:38:53.373 --> 00:38:56.723 to join these two pieces of armored plate. 792 00:38:56.723 --> 00:38:58.148 (dramatic music) 793 00:38:58.148 --> 00:39:00.981 (machine banging) 794 00:39:01.910 --> 00:39:04.963 A special hammer drives the rivet into place. 795 00:39:07.470 --> 00:39:09.970 (soft music) 796 00:39:10.900 --> 00:39:13.050 - Japanese sailors assigned to Musashi 797 00:39:13.050 --> 00:39:15.410 had great confidence in the ship. 798 00:39:15.410 --> 00:39:17.730 They thought it was unsinkable, and that's because, 799 00:39:17.730 --> 00:39:20.200 above deck, they saw nothing but guns and firepower. 800 00:39:20.200 --> 00:39:21.670 But then below deck, they were aware 801 00:39:21.670 --> 00:39:23.830 that the ship had the thickest armor 802 00:39:23.830 --> 00:39:25.230 of any warship in the world. 803 00:39:26.420 --> 00:39:28.750 - [Narrator] But the Japanese investigation team 804 00:39:28.750 --> 00:39:31.113 doesn't share the sailors' confidence. 805 00:39:32.130 --> 00:39:34.263 (Hayao speaks in foreign language) 806 00:39:34.263 --> 00:39:36.100 - [Interpreter] I think rivets were the problem. 807 00:39:36.100 --> 00:39:38.050 No matter how thick the armor plates were, 808 00:39:38.050 --> 00:39:40.350 they wouldn't last once the rivets came loose. 809 00:39:41.439 --> 00:39:43.040 - [Narrator] Musashi's armor was attached 810 00:39:43.040 --> 00:39:47.133 at a slanting angle to deflect incoming shells. 811 00:39:48.023 --> 00:39:49.450 (man speaks in foreign language) 812 00:39:49.450 --> 00:39:51.850 - [Interpreter] She was built to withstand artillery duels 813 00:39:51.850 --> 00:39:54.030 against other battleships. 814 00:39:54.030 --> 00:39:57.740 But, instead, she was hit by torpedoes and aerial bombs, 815 00:39:57.740 --> 00:40:00.530 which weren't weapons she expected to face 816 00:40:00.530 --> 00:40:01.884 when she was designed. 817 00:40:01.884 --> 00:40:04.467 (guns popping) 818 00:40:05.580 --> 00:40:08.480 - [Narrator] If a torpedo from an attacking aircraft 819 00:40:08.480 --> 00:40:10.960 struck a a joint in the armor plate, 820 00:40:10.960 --> 00:40:13.922 it could cause rivets to fail and seawater 821 00:40:13.922 --> 00:40:16.254 to begin to seep in. 822 00:40:16.254 --> 00:40:19.960 (plane engine roaring) 823 00:40:19.960 --> 00:40:22.360 So how did this apparent vulnerability 824 00:40:22.360 --> 00:40:25.270 to torpedo strikes go unnoticed? 825 00:40:25.270 --> 00:40:26.647 (guns banging) 826 00:40:26.647 --> 00:40:27.745 (light music) 827 00:40:27.745 --> 00:40:31.995 (men speaking in foreign language) 828 00:40:33.150 --> 00:40:35.430 The team discovers early concerns 829 00:40:35.430 --> 00:40:37.553 about this possible design flaw. 830 00:40:39.860 --> 00:40:42.310 A former officer on Musashi, 831 00:40:42.310 --> 00:40:45.480 who earlier served on her sister ship, Yamato, 832 00:40:45.480 --> 00:40:47.923 made this recording before he died. 833 00:40:49.182 --> 00:40:51.890 (Haruo speaks in foreign language) 834 00:40:51.890 --> 00:40:53.478 - [Interpreter] I heard from Yamato's crew 835 00:40:53.478 --> 00:40:56.150 that during a torpedo attack, 836 00:40:56.150 --> 00:40:58.520 although the armor remained intact, 837 00:40:58.520 --> 00:41:00.410 the rivets were blown off, 838 00:41:00.410 --> 00:41:04.670 and, gradually, water started to leak in around the joints. 839 00:41:04.670 --> 00:41:08.700 It made me realize, if we were hit by a lot of torpedoes, 840 00:41:08.700 --> 00:41:10.062 there would be more flooding, 841 00:41:10.062 --> 00:41:11.973 and that could be her weakest point. 842 00:41:13.050 --> 00:41:15.680 - [Narrator] Shigeru Makino, a naval designer 843 00:41:15.680 --> 00:41:18.290 who oversaw the construction of Musashi, 844 00:41:18.290 --> 00:41:23.137 reported similar misgivings, but later wrote, 845 00:41:23.137 --> 00:41:24.857 "The naval authorities decided 846 00:41:24.857 --> 00:41:27.377 "to simply patch the armor joint 847 00:41:27.377 --> 00:41:30.427 "rather than find a permanent solution to the problem." 848 00:41:32.360 --> 00:41:35.610 In the minds of Musashi's 2,400 crewmen, 849 00:41:35.610 --> 00:41:38.490 many still in their teens or early 20s, 850 00:41:38.490 --> 00:41:43.260 the Imperial Japanese Navy instilled a beguiling illusion, 851 00:41:43.260 --> 00:41:48.140 their super battleship was quite simply unsinkable. 852 00:41:49.172 --> 00:41:50.880 (soft music) 853 00:41:50.880 --> 00:41:55.880 One of them, Masahiro Ohishi, believed it to the very end. 854 00:41:55.987 --> 00:41:57.740 (Masahiro speaks in foreign language) 855 00:41:57.740 --> 00:41:59.770 - [Interpreter] Right up till the moment it sank, 856 00:41:59.770 --> 00:42:01.780 I didn't think it could happen. 857 00:42:01.780 --> 00:42:04.190 The Musashi wouldn't even budge an inch 858 00:42:04.190 --> 00:42:06.650 with a torpedo or two striking her. 859 00:42:06.650 --> 00:42:09.713 There would be no flooding, so we were told. 860 00:42:11.610 --> 00:42:13.830 - [Narrator] Musashi also proved vulnerable 861 00:42:13.830 --> 00:42:15.993 to another unanticipated weapon, 862 00:42:17.180 --> 00:42:19.483 armor-piercing bombs from the air, 863 00:42:20.700 --> 00:42:23.145 as the search team discovered. 864 00:42:23.145 --> 00:42:25.130 - [Man] See that's an issue. 865 00:42:25.130 --> 00:42:27.397 - [Rob] Yeah, once you get in there a little tighter-- 866 00:42:28.290 --> 00:42:29.777 - [Narrator] Underwater footage revealed 867 00:42:29.777 --> 00:42:33.383 one of several 3-foot holes rupturing the ships deck. 868 00:42:34.810 --> 00:42:36.380 - In a short section of the bow, 869 00:42:36.380 --> 00:42:38.370 we saw the damage from the bombs. 870 00:42:38.370 --> 00:42:41.780 So that's corroborating what the US pilots were telling us 871 00:42:41.780 --> 00:42:44.690 about the hits they were getting on Musashi. 872 00:42:44.690 --> 00:42:47.420 - These weapons, although they are as crude and as simple 873 00:42:47.420 --> 00:42:50.880 as they can be, sent through the air column, 874 00:42:50.880 --> 00:42:54.400 penetrate decks and can explode below deck. 875 00:42:54.400 --> 00:42:57.763 This, in the end, causes great destruction on Musashi. 876 00:42:58.854 --> 00:43:00.780 (soft dramatic music) 877 00:43:00.780 --> 00:43:03.970 - [Narrator] Now, thanks to the 3D model of the wreck, 878 00:43:03.970 --> 00:43:06.723 the full extent of that destruction can be seen, 879 00:43:07.610 --> 00:43:09.934 especially up on the bridge, where the captain 880 00:43:09.934 --> 00:43:12.203 and many of officers were stationed. 881 00:43:14.700 --> 00:43:18.680 A gaping 20-foot hole gouged into the starboard side 882 00:43:18.680 --> 00:43:20.563 marks where a bomb struck. 883 00:43:24.860 --> 00:43:28.493 One crew member up here miraculously survived. 884 00:43:29.910 --> 00:43:32.633 Kenji Otsuka remembers what happened. 885 00:43:33.928 --> 00:43:37.940 (Kenji speaks in foreign language) 886 00:43:37.940 --> 00:43:40.390 - [Interpreter] All the desks, chairs, everything, 887 00:43:40.390 --> 00:43:42.550 flew to the port side. 888 00:43:42.550 --> 00:43:46.110 Bodies of those who were killed were piled up there, too. 889 00:43:46.110 --> 00:43:49.440 The blast wave knocked us over, killing some. 890 00:43:49.440 --> 00:43:52.020 One man lost everything from his neck up, 891 00:43:52.020 --> 00:43:54.070 sitting in a chair about 10-feet 892 00:43:54.070 --> 00:43:57.093 from where I was, just dead. 893 00:44:00.730 --> 00:44:03.450 - [Narrator] Standing on an open observation deck, 894 00:44:03.450 --> 00:44:07.570 Captain Inoguchi suffered a shrapnel wound in the shoulder. 895 00:44:07.570 --> 00:44:09.543 Protected from the fire himself, 896 00:44:10.400 --> 00:44:12.833 crewman Kotaki observed what happened. 897 00:44:13.797 --> 00:44:15.790 (Tatsuo speaks in foreign language) 898 00:44:15.790 --> 00:44:17.220 - [Interpreter] I saw him from behind. 899 00:44:17.220 --> 00:44:20.250 He was covering his shoulder with his hand like this, 900 00:44:20.250 --> 00:44:24.130 holding binoculars like this, and giving commands. 901 00:44:24.130 --> 00:44:27.810 Any ordinary person would have collapsed from such injuries. 902 00:44:27.810 --> 00:44:30.337 I thought, "That's a true commander." 903 00:44:31.450 --> 00:44:33.040 - [Narrator] Like her brave captain, 904 00:44:33.040 --> 00:44:35.160 Musashi sustained multiple hits 905 00:44:35.160 --> 00:44:37.823 from weapons she was never designed to face. 906 00:44:39.270 --> 00:44:42.520 Incredibly, her unusual strength allowed her 907 00:44:42.520 --> 00:44:46.263 to go down in one piece, leaving one final question, 908 00:44:47.250 --> 00:44:49.907 what tore her to pieces as she sank? 909 00:44:49.907 --> 00:44:52.651 (water splashing) 910 00:44:52.651 --> 00:44:54.333 (dramatic music) 911 00:44:54.333 --> 00:44:55.672 - [David] That's a 46-centimeter shell 912 00:44:55.672 --> 00:44:56.883 underneath there, right? 913 00:44:57.750 --> 00:44:58.960 - [Narrator] When the search team 914 00:44:58.960 --> 00:45:01.220 originally discovered Musashi-- 915 00:45:01.220 --> 00:45:03.020 - The turret housing was blown away. 916 00:45:04.340 --> 00:45:05.800 - [Narrator] They couldn't believe the wreckage 917 00:45:05.800 --> 00:45:08.193 was spread over such a wide area, 918 00:45:09.750 --> 00:45:14.120 a square kilometer, more than half a square mile. 919 00:45:14.120 --> 00:45:16.020 - Most of the shipwrecks that I've done 920 00:45:16.020 --> 00:45:17.830 are in deeper water than this, 921 00:45:17.830 --> 00:45:21.160 and we're seeing debris fields of 300 meters, 400 meters. 922 00:45:21.160 --> 00:45:23.690 So to see one twice or three times that size 923 00:45:23.690 --> 00:45:25.720 is really telling me that not only 924 00:45:25.720 --> 00:45:27.070 are we dealing with a large ship, 925 00:45:27.070 --> 00:45:29.164 but a large ship that has been blown apart. 926 00:45:29.164 --> 00:45:30.470 (man speaks in foreign language) 927 00:45:30.470 --> 00:45:33.920 - [Narrator] How does a ship that left the surface intact 928 00:45:33.920 --> 00:45:37.840 now lie shattered over the ocean floor? 929 00:45:37.840 --> 00:45:40.930 The Japanese team is determined to find an answer 930 00:45:40.930 --> 00:45:43.633 to this final mystery of Musashi. 931 00:45:43.633 --> 00:45:46.230 (man speaks in foreign language) 932 00:45:46.230 --> 00:45:47.930 - [Interpreter] I'm not sure if it came from a boiler 933 00:45:47.930 --> 00:45:50.530 or something else, but is it possible 934 00:45:50.530 --> 00:45:52.793 this damage was caused by steam exploding? 935 00:45:53.810 --> 00:45:55.860 - [Narrator] One member doesn't think so. 936 00:45:57.348 --> 00:45:59.140 Masatake Yoshida has been studying explosives 937 00:45:59.140 --> 00:46:01.150 for over 30 years. 938 00:46:01.150 --> 00:46:04.788 He believes something else tore Musashi apart. 939 00:46:04.788 --> 00:46:07.820 (Masatake speak in foreign language) 940 00:46:07.820 --> 00:46:09.480 - [Interpreter] I can't think of any explanation 941 00:46:09.480 --> 00:46:11.830 besides a gunpowder explosion. 942 00:46:11.830 --> 00:46:13.920 If an explosion like that occurred, 943 00:46:13.920 --> 00:46:16.677 her internal parts would have shattered into many pieces. 944 00:46:16.677 --> 00:46:18.950 (soft music) 945 00:46:18.950 --> 00:46:19.783 - [Narrator] But where did 946 00:46:19.783 --> 00:46:21.943 this massive explosion take place? 947 00:46:22.780 --> 00:46:25.120 One piece of debris in particular 948 00:46:25.120 --> 00:46:26.933 has caught Yoshida's attention. 949 00:46:28.510 --> 00:46:31.283 Although mangled almost beyond recognition, 950 00:46:32.120 --> 00:46:35.020 it's part of the magazine, holding the shells 951 00:46:35.020 --> 00:46:37.193 for one of Musashi's main guns. 952 00:46:38.128 --> 00:46:42.950 (Masatake speaks in foreign language) 953 00:46:42.950 --> 00:46:44.110 - [Interpreter] Thick steel like this 954 00:46:44.110 --> 00:46:46.800 wouldn't have ended up being so badly twisted 955 00:46:46.800 --> 00:46:48.290 if the ship had just sunk. 956 00:46:49.740 --> 00:46:51.850 - [Narrator] Since Musashi fired her main guns 957 00:46:51.850 --> 00:46:55.360 only a handful of times during her final battle, 958 00:46:55.360 --> 00:46:59.560 an estimated 160 shells and 100 tons of gunpowder 959 00:46:59.560 --> 00:47:01.263 were still stored inside her. 960 00:47:03.149 --> 00:47:05.420 (soft dramatic music) 961 00:47:05.420 --> 00:47:08.310 Suspicion as to where the explosion occurred 962 00:47:08.310 --> 00:47:10.806 falls on the second main gun. 963 00:47:10.806 --> 00:47:12.050 - [David] So that was literally-- 964 00:47:12.050 --> 00:47:13.400 - [Narrator] And firsthand reports 965 00:47:13.400 --> 00:47:16.790 David Mearns uncovered seem to support it. 966 00:47:16.790 --> 00:47:18.990 - To see that level of damage on the seafloor 967 00:47:18.990 --> 00:47:22.800 tells me only one thing, that the Japanese survivors 968 00:47:22.800 --> 00:47:25.970 who heard explosions as it was capsizing, 969 00:47:25.970 --> 00:47:28.593 those explosions were actually magazine explosions. 970 00:47:30.670 --> 00:47:31.920 - [Narrator] In the final moments, 971 00:47:31.920 --> 00:47:35.090 as Musashi heeled over and sank, 972 00:47:35.090 --> 00:47:37.960 a few eyewitnesses aboard a nearby destroyer 973 00:47:37.960 --> 00:47:41.013 reported seeing the flash from a small explosion. 974 00:47:41.913 --> 00:47:44.090 (Masatake speaks in foreign language) 975 00:47:44.090 --> 00:47:45.360 - [Interpreter] Which means that some fires 976 00:47:45.360 --> 00:47:47.730 were already burning inside her. 977 00:47:47.730 --> 00:47:49.760 That makes me think that initial combustion 978 00:47:49.760 --> 00:47:52.673 rapidly spread into an explosion. 979 00:47:52.673 --> 00:47:56.600 Gunpowder contains some oxygen, so even underwater 980 00:47:56.600 --> 00:47:59.670 where there's none, under the right conditions, 981 00:47:59.670 --> 00:48:02.470 a combustive explosion can occur. 982 00:48:02.470 --> 00:48:04.360 - [Narrator] To test his hypothesis, 983 00:48:04.360 --> 00:48:07.453 Dr. Yoshida ran a computer simulation. 984 00:48:09.101 --> 00:48:13.050 It clearly shows a ship made of heavy steel 985 00:48:13.050 --> 00:48:15.266 would have suffered catastrophic damage 986 00:48:15.266 --> 00:48:18.657 from an explosion below her second main gun. 987 00:48:18.657 --> 00:48:21.460 (dramatic music) 988 00:48:21.460 --> 00:48:23.440 The ships core would have splintered 989 00:48:23.440 --> 00:48:25.250 into hundreds of small pieces 990 00:48:26.230 --> 00:48:30.023 with only the bow and stern remaining relatively intact. 991 00:48:33.100 --> 00:48:36.440 The high-resolution sonar map confirms, 992 00:48:36.440 --> 00:48:39.043 this is how the wreck rests on the seafloor. 993 00:48:44.370 --> 00:48:47.500 David Mearns believes other factors also contributed 994 00:48:47.500 --> 00:48:50.970 to the massive damage sustained by Musashi. 995 00:48:50.970 --> 00:48:53.781 (soft dramatic music) 996 00:48:53.781 --> 00:48:57.310 - We see that a large section of the bow was imploded 997 00:48:57.310 --> 00:48:58.900 and we can look at the drawings and know 998 00:48:58.900 --> 00:49:00.750 that there's water-tight compartments in there, 999 00:49:00.750 --> 00:49:03.733 and they've squeezed as the ship sank very quickly. 1000 00:49:05.450 --> 00:49:08.110 - [Narrator] As Musashi plummets to the bottom, 1001 00:49:08.110 --> 00:49:11.210 a crushing pressure, equivalent to the weight of a car, 1002 00:49:11.210 --> 00:49:13.463 bears down on every square inch. 1003 00:49:14.905 --> 00:49:17.210 - When it hits the sea bed, it's hitting the seabed, 1004 00:49:17.210 --> 00:49:19.760 actually, at very high speed, probably a minimum 1005 00:49:19.760 --> 00:49:22.670 of 15 knots, maybe as much as 25 knots. 1006 00:49:22.670 --> 00:49:24.083 And there's impact damage. 1007 00:49:24.960 --> 00:49:27.763 And all of this was evident in one section of the bow. 1008 00:49:30.770 --> 00:49:33.670 - [Narrator] Somewhere in Musashi's twisted remains 1009 00:49:33.670 --> 00:49:36.973 lies her captain, Toshihira Inoguchi. 1010 00:49:37.924 --> 00:49:39.640 He went down with his ship 1011 00:49:39.640 --> 00:49:41.883 after handing over his final report. 1012 00:49:44.242 --> 00:49:47.947 In it, he wrote, "I am truly glad 1013 00:49:47.947 --> 00:49:51.113 "that the other battleship suffered almost no damage, 1014 00:49:52.237 --> 00:49:54.727 "and I feel some consolation in thinking 1015 00:49:54.727 --> 00:49:58.277 "that Musashi was able to assume the role of a victim." 1016 00:50:00.793 --> 00:50:02.617 (dramatic music) 1017 00:50:02.617 --> 00:50:04.264 (plane engines roaring) 1018 00:50:04.264 --> 00:50:05.507 (torpedoes banging) 1019 00:50:05.507 --> 00:50:06.920 - [Narrator] Musashi bore the brunt 1020 00:50:06.920 --> 00:50:10.700 of the American air assault on October 24th, 1944, 1021 00:50:10.700 --> 00:50:13.785 (torpedoes banging) 1022 00:50:13.785 --> 00:50:17.780 leaving most of Japan's Center Force unscathed, 1023 00:50:17.780 --> 00:50:20.093 including the super battleship, Yamato. 1024 00:50:23.570 --> 00:50:25.720 Undetected, Admiral Kurita 1025 00:50:25.720 --> 00:50:28.770 and his 20 remaining ships steamed through the night 1026 00:50:32.330 --> 00:50:34.630 heading for the American landing site at Leyte 1027 00:50:38.000 --> 00:50:41.443 to catch the defending force from 7th fleet by surprise. 1028 00:50:45.430 --> 00:50:49.261 On October 25th, led by the super battleship, Yamato, 1029 00:50:49.261 --> 00:50:50.094 (guns banging) 1030 00:50:50.094 --> 00:50:53.390 the Japanese Navy launched the decisive surface attack 1031 00:50:53.390 --> 00:50:54.423 it had long sought. 1032 00:50:56.970 --> 00:50:59.370 But a bold strike by American destroyers 1033 00:50:59.370 --> 00:51:01.910 and destroyer escorts managed to confuse 1034 00:51:01.910 --> 00:51:03.283 the Japanese commander. 1035 00:51:06.520 --> 00:51:09.650 - And so Admiral Kurita makes the fateful decision 1036 00:51:09.650 --> 00:51:12.560 to reverse course, and in so doing, 1037 00:51:12.560 --> 00:51:15.555 he walks away from what would have been 1038 00:51:15.555 --> 00:51:19.990 the most lopsided victory of the Japanese Imperial Navy 1039 00:51:19.990 --> 00:51:21.190 in the Second World War. 1040 00:51:22.410 --> 00:51:24.100 - [Narrator] Japan's Navy had gambled 1041 00:51:24.100 --> 00:51:26.400 on winning the world's biggest sea battle 1042 00:51:26.400 --> 00:51:28.803 to bring America to the negotiating table. 1043 00:51:30.060 --> 00:51:32.113 But they made a fatal miscalculation. 1044 00:51:33.095 --> 00:51:35.770 Surface ships with big guns 1045 00:51:35.770 --> 00:51:38.393 were no longer the dominant force at sea. 1046 00:51:40.740 --> 00:51:42.210 - The age of the battleships, 1047 00:51:42.210 --> 00:51:45.750 the building and the loss of the Musashi is the endpoint. 1048 00:51:45.750 --> 00:51:48.010 They weren't gonna be defeated by another battleship, 1049 00:51:48.010 --> 00:51:50.850 another great battleship, but by aircraft. 1050 00:51:50.850 --> 00:51:54.777 And that's when the era of aircraft carriers took off. 1051 00:51:59.993 --> 00:52:03.160 (soft dramatic music) 1052 00:52:06.400 --> 00:52:11.400 On October 24th, 2016, at Yasukuni Shrine in Tokyo, 1053 00:52:11.980 --> 00:52:14.410 surviving crew members from Musashi 1054 00:52:14.410 --> 00:52:16.773 gathered to remember their lost comrades. 1055 00:52:18.520 --> 00:52:21.780 The discovery of the wreck and the evidence it reveals 1056 00:52:21.780 --> 00:52:25.113 of Musashi's vulnerability is a cruel reminder, 1057 00:52:26.310 --> 00:52:28.073 this was not the unsinkable battleships 1058 00:52:28.073 --> 00:52:30.063 they were led to believe her to be. 1059 00:52:32.430 --> 00:52:33.913 But for crewman Tsukada, 1060 00:52:34.800 --> 00:52:37.333 the wreck still bears an important message. 1061 00:52:38.927 --> 00:52:41.460 (Yoshiaki speaks in foreign language) 1062 00:52:41.460 --> 00:52:42.726 - [Interpreter] I think the Musashi 1063 00:52:42.726 --> 00:52:44.370 would like the people to know 1064 00:52:44.370 --> 00:52:47.430 how bravely her crew members fought and died. 1065 00:52:47.430 --> 00:52:49.942 What an astonishing battleship she was, 1066 00:52:49.942 --> 00:52:53.200 how she fought and met her tragic end 1067 00:52:53.200 --> 00:52:57.630 in the emptiness of war, I think those are the messages 1068 00:52:57.630 --> 00:53:00.672 that the Musashi wants to send us. 1069 00:53:00.672 --> 00:53:03.720 (soft music) 1070 00:53:03.720 --> 00:53:06.174 - [Narrator] For Bob Freligh, an American pilot who launched 1071 00:53:06.174 --> 00:53:09.326 one of the many torpedoes that sank her, 1072 00:53:09.326 --> 00:53:13.333 Musashi's discovery stirs thoughts of reconciliation. 1073 00:53:14.410 --> 00:53:17.210 - I don't want any Japanese survivor 1074 00:53:17.210 --> 00:53:21.340 to think that I'm trying to laud these medals over them. 1075 00:53:21.340 --> 00:53:24.300 Our opportunity is, we have a common ground. 1076 00:53:24.300 --> 00:53:26.880 They are survivors of the same action 1077 00:53:26.880 --> 00:53:29.030 that I'm a survivor of, 1078 00:53:29.030 --> 00:53:33.753 and I'd just like to say, welcome, brother. 1079 00:53:39.615 --> 00:53:42.198 (bell dinging) 1080 00:53:43.237 --> 00:53:44.910 - "At the going down with the sun, 1081 00:53:44.910 --> 00:53:47.873 and in the morning we will remember them." 1082 00:53:47.873 --> 00:53:50.373 - [All] We will remember them. 1083 00:53:51.470 --> 00:53:52.580 - [Narrator] Above the wreck site 1084 00:53:52.580 --> 00:53:54.250 in the Sibuyan Sea, (somber horn music) 1085 00:53:54.250 --> 00:53:57.523 the crew of the Octopus pay their own final respects. 1086 00:53:58.434 --> 00:54:00.300 - It is a war grave. 1087 00:54:00.300 --> 00:54:02.900 You know, we as sailors and seafarers ourselves, 1088 00:54:02.900 --> 00:54:05.077 we have a lot of respect for what happened here. 1089 00:54:05.077 --> 00:54:07.870 (soft music) 1090 00:54:07.870 --> 00:54:09.545 - [Narrator] Instead of warplanes, 1091 00:54:09.545 --> 00:54:12.083 they launch a flight of paper cranes, 1092 00:54:13.640 --> 00:54:15.550 symbol of the peace that has endured 1093 00:54:15.550 --> 00:54:18.032 for three-quarters of a century 1094 00:54:18.032 --> 00:54:20.913 between once bitter enemies of World War II. 1095 00:54:27.286 --> 00:54:30.619 (soft dramatic music)