Rot, Heat, and Depth Charges — The Nightmare Inside Japanese WWII Submarines

Added: 2026-05-15

[00:00:00]the low suffocating hum of a diesel engine. A single drop of water hits metal somewhere in the dark. Imagine being locked inside a steel pipe 90 ft below the Pacific Ocean with a 100 other men who haven't bathed in weeks. The air is so thick with diesel fume, sweat, and mold that you can taste it. The temperature never drops below 100°. Your bunk isn't yours. Two other men sleep in it when you're on watch. There is no night. There is no day. There is only the hum of the engine and the knowledge that a single depth charge could turn this pipe into your coffin. Now imagine something worse. Somewhere on this submarine bolted to the deck above you.

[00:00:42]There are six metal cylinders, each one carrying a man. These men climbed involuntarily. They will be launched like torpedoes at enemy ships. They will not come back. And the youngest of them is 17 years old. Not old enough to vote.

[00:00:58]old enough to die. This was the Imperial Japanese Navy submarine fleet during World War II, a force that fielded the largest, most technologically advanced submarines on Earth and lost nearly all of them. This is the story of one man who served on these boats from the first day of the war to the last. His name was Hashimoto Mochitsura. He fired the torpedoes that sank the USS Indianapolis, the worst disaster at sea in American naval history. And when he finally came home, he discovered that his family had been destroyed by the very bomb his target had recently delivered. Kyoto 1909. In a quiet neighborhood on the western edge of the city behind the wooden Tori gate of Umomia Taisha, a Shinto shrine older than most countries on earth, a boy was born, the eighth child, the fifth son.

[00:01:50]His father was a kanushi, a Shinto priest whose family had tended the shrine for generations. The salary was modest. The mouths to feed were manny, and one by one, the older sons left home for the military because a uniform paid better than prayers. The boy's name was Hashimoto Mochura. He was quiet, self-possessed, respectful, the kind of child who listened before he spoke and watched before he moved. His father wanted him to follow the family tradition to take over the shrine someday. But the priest was also a practical man. He could barely feed his children on a government subsidy. So when the time came, it was his father, not young Hashimoto, who made the decision. In 1927, at 17 years old, Hashimoto left Kyoto for the Imperial Japanese Naval Academy on the island of Itajima. He would not return for a very long time. For four years he studied naval tactics engineering Japanese history. He practiced judo. He learned to think in distances and trajectories in knots and fathoms. He graduated in 1931 commissioned as an nsign and then he did something unusual. He volunteered for submarines in the Imperial Japanese Navy of the 1930s. This was not a glamorous choice. Surface ships, battleships, cruisers, carriers. Those were where careers were made. Submarines were something else entirely. They were dark. They were cramped. They smelled like diesel fuel and sweat and rust. The men who served on them were a particular breed, quiet, methodical, comfortable with confinement. Hashimoto fit the description perfectly. By 1937, he had married Noubuku Miki, the daughter of a successful Osaka businessman. They would eventually have three sons, Mochiro Nouake and Tommoyuki. That same year, while serving aboard destroyers and submarine chasers off the coast of China, Hashimoto received word that one of his older brothers had been killed in action on the Chinese mainland. The war had already started for his family. the rest of the world just hadn't noticed yet. He entered the Navy Tofido school in 1939, then submarine school. He studied the mechanics of killing from underwater, how a torpedo moved through water, how to calculate the angle, the speed, the lead. He became very good at it. By the summer of 1941, Lieutenant Hashimoto was assigned as torpedo officer aboard the submarine I24 under the command of Lieutenant Commander Hanabusa Hiroshi, based out of the naval port at Kur. And it was aboard I24 that he first learned what the Imperial Japanese Navy truly expected of its men. Throughout 1941, I24 conducted training exercises with a group of [ __ ] submarines. Tiny twoman vessels barely 78 ft long, armed with a pair of torpedoes, and powered by batteries that lasted less than an hour at full speed. They were crude, they were fragile, and they were designed to be carried on the back of a full-size submarine, then released near an enemy harbor to sneak inside and attack. The men who crewed them understood what this meant. The batteries wouldn't last long enough to get back. The plan included a rendevous point for retrieval, but everyone involved knew the odds. These missions were for all practical purposes one-way trips wrapped in the thin language of a return ticket. On November 18th, 1941, I24 slipped out of Kur Harbor with one of these [ __ ] submarines strapped to her after deck.

[00:05:45]Aboard the tiny vessel were two men and signin Sakamaki Kazuo, 23 years old, and chief warrant officer Inagaki Koshi.

[00:05:54]Hashimoto watched them prepare. He watched Sakamaki write a final letter to his parents. He watched Inagaki check the instruments one last time. He watched both men go through the ritual with steady hands and calm faces, the way men do when they have already accepted what is coming. There was a problem. The gyroscope, the instrument that kept the submarine on course underwater, was broken. Sakamaki knew, Inagaki knew they chose to go anyway. I 24 steamed east across the Pacific for 18 days. Clogged pumps, defective valves, general misery.

[00:06:33]On December 6th, the submarine surfaced 10 mi off Waiki in the darkness before dawn. The [ __ ] sub was readied. At 3:33 in the morning, Sakamaki and Inagaki cast off. I24 waited at the rendevous point. Hours passed. The attack on Pearl Harbor erupted above the waterline. The roar of aircraft. The thunder of bombs columns of black smoke visible even from beneath the sea. And still Hashimoto waited. The [ __ ] submarine never came back. On December 9th, I24 turned for home. Hashimoto did not know what had happened to the two men. He would not learn the full story until later. And when he did, it would teach him something about the Navy. He served a lesson more brutal than any torpedo could deliver. Here is what happened to Sakamaki Kazu. The broken gyroscope made the [ __ ] submarine nearly impossible to steer. It hit coral reefs not once, not twice, but multiple times. Salt water flooded the battery compartment producing chlorine gas that filled the tiny cockpit and knocked both men unconscious over and over. They came to They tried again. The destroyer USS Helm spotted them stuck on a reef and opened fire. The shells missed, but the concussion knocked Sakamaki unconscious again and freed the submarine from the rocks. By then, the torpedo tubes were crushed. The batteries were dying. There was nothing left to do. Sakamaki lit a fuse to destroy the submarine and both men jumped into the surf. Inagi never made it to shore. He drowned in the waves. His body never recovered.

[00:08:18]Sakamaki washed up on Wmanalo beach unconscious. An American soldier, Sergeant David Aku, a man of Japanese descent, found him lying on the sand the next morning. Kazuo Sakamaki became prisoner of war number one. The first Japanese serviceman captured by American forces in the Second World War. Of the 10 men who had set out in five [ __ ] submarines to attack Pearl Harbor, Nina were dead. They were celebrated as heroes. Shrines were built. Songs were written. Their names were etched into the national memory. Sakamaki was alive and for that he was erased. The Imperial Japanese Navy struck his name from the records. His family was told he had been killed in action. Admiral Yamamoto was reportedly furious, not that the mission had failed, but that one of the men had been taken alive. It was in the eyes of the command the ultimate disgrace.

[00:09:14]Sakamaki held in an American hospital under armed guard asked to be allowed to kill himself. The request was denied.

[00:09:22]His submarine HA19 was pulled from the reef, shipped to the mainland, and sent on a tour across the United States to sell war bonds. The machine was more useful to America than the man had been to Japan, and this was the lesson Hashimoto carried with him. As I 24 steamed back to Kur in the winter of 1941, though he may not have fully understood it yet. In the Imperial Japanese Navy, the line between a hero and a disgrace was not drawn by courage or skill or duty. It was drawn by a single question. Did you die if yes, you were a god? If no, you were nothing.

[00:10:02]Hashimoto would spend the next four years watching this logic consume everything around him. the men, the machines, and eventually the empire itself. But in December 1941, the war was just beginning. Japan had struck first. The Pacific was burning, and the submarine force, the largest, most diverse, most technologically advanced underwater fleet on the planet, was about to sail into the kind of war it was never designed to fight and lose. In the first year of the war, the Imperial Japanese Navy submarine fleet did something no other undersea force had ever done. On September 15th, 1942, south of the Solomon Islands, the submarine I19 under commander Kinashi Takazu fired six torpedoes at the American aircraft carrier USS Wasp.

[00:10:51]Three hit the Wasp directly. Fires erupted across the flight deck fuel lines, ruptured ammunition cooked off in the magazines. Within 5 hours, the ship was abandoned.

[00:11:02]193 American sailors were dead. The carrier slipped beneath the waves at 9:00 that evening, but the other three torpedoes kept going. They traveled five more miles through open water and struck two different ships in a completely separate task force. One hid the battleship USS North Carolina, tearing a 32 by8 ft hole in her port side. Another hit the destroyer USS O'Brien cracking a hull so badly that she broke apart and sank a month later on the way to dry dock. One submarine, one salvo, one carrier sunk, one battleship crippled, one destroyer destroyed. It remains one of the most devastating torpedo attacks in the history of naval warfare. And it was a lie. Not the attack itself that happened exactly as described. The lie was what the Japanese high command believed it proved. They looked at I19 success and saw confirmation that their submarines should keep doing exactly what they had been doing, hunting warships. Fast maneuverable, heavily defended warships. The targets that shot back. The targets surrounded by destroyers whose only job was to find submarines and kill them. Meanwhile, thousands of slow-fat, barely defended American merchant ships were crossing the Pacific every month carrying oil, steel, food, ammunition, rubber.

[00:12:28]Everything an army needs to fight a war.

[00:12:30]And the Japanese submarine force was ordered to leave them alone. This was the doctrine of Kai Kessan, the decisive battle. One great clash that would end the war in a single afternoon. The way Admiral Togo had destroyed the Russian fleet at Tsushima in 1905. Every branch of the Imperial Navy surface ships aircraft submarines existed to serve this one idea. Submarines were scouts.

[00:12:55]Their job was to find the enemy fleet shadow it and pick off warships before the grand battle began. It was a beautiful theory. It was also a death sentence. By the end of the war, Japan's submarines had sunk just 184 merchant ships, about 97,000 tons. Germany's yubot sank 2,840 merchant ships, over 14 million tons.

[00:13:20]American submarines, meanwhile, were tearing Japan apart from below. They sank over 1,300 Japanese ships, 5.3 million tons cutting off the oil from the Dutch East Indies, the iron ore from Manuria, the rice from Southeast Asia.

[00:13:37]By early 1945, Japan's fuel tanks were dry, factories sat idle, ships couldn't sail because there was nothing left to burn. The Japanese submarine force had the technology to do the same thing to America. They had the range. They had the torpedoes. They had the boats. What they didn't have was permission. And so they hunted warships. And the warships hunted them back. Here is what it felt like to die slowly inside a Japanese submarine. The boats were enormous, the largest in the world. Some stretched over 400 ft longer than a football field. They carried float planes in waterproof hangers. They crossed oceans without refueling. From the outside, they were marvels of engineering. From the inside, they were ovens. When the submarine ran on the surface at night, which was the only safe time since American aircraft owned the daylight, the diesel engines generated enormous heat. This heat soaked into the steel walls, the pipes, the floor, the ceiling. Then the submarine dove at dawn to hide. The diesel shut down. The electric motors took over. And all that stored heat had nowhere to go. It spread through every compartment, every passageway, every bunk. Temperatures in the engine room exceeded 100° F. The rest of the boat wasn't much better. The air turned thick and wet. Condensation dripped from every surface. Mold grew on clothing, on food, on skin. There was almost no fresh water. On long patrols, men went weeks without bathing. Laundry was impossible. The smell inside a submarine was something you could never forget and never describe accurately. A mixture of diesel fuel, human sweat, hydraulic fluid, cooking oil, mildew, and sewage all baked together in a sealed metal tube. And then there were the cockroaches. They bred in the dark spaces behind instruments inside wall cavities under bunks. Crews tried everything to get rid of them. Nothing worked. They were a permanent feature of life aboard skittering across faces in the dark, crawling over food left unattended for 10 seconds. Bunks were shared. They called it hot racking two or three men rotating through the same narrow mattress in shifts. When one man got up for his watch, the next man climbed in. The sheets, if they could be called sheets, were always damp, always warm, always carrying the smell of the man who had just left. The men knew the air was getting bad when they couldn't light their cigarettes, not because of any regulation, because there wasn't enough oxygen left in the atmosphere to sustain a flame. When a match wouldn't strike, it meant the boat had been submerged too long. It meant the carbon dioxide was building. It meant headaches, dizziness, confusion, and it meant that somewhere above them, an enemy ship was circling, waiting, listening. Because by 1943, the Americans had learned how to find them.

[00:16:39]The problem was size. Japanese submarines were built to cross oceans.

[00:16:44]That required massive hulls, huge fuel tanks, powerful engines, but all of that made them easy to detect visually on radar and on sonar. Compared to German Ubot, Japanese submarines were slow to dive hard to maneuver underwater, easy to track, and easy to hit. Their hulls were also weaker. German boats could dive below 700 ft. Japanese boats often couldn't go past 300 without risking catastrophic failure. When depth charges started falling, and by 1943, American destroyers were dropping them. With increasing accuracy, Japanese submarines had nowhere to hide. A depth charge didn't have to hit the submarine directly. It just had to get close. The shock wave traveled through water at tremendous speed and struck the hull like a giant hammer. Light bulbs shattered, pipes burst, gauges cracked.

[00:17:39]In the sudden darkness, water began seeping through rivets, through seams, through places that had never leaked before. The men inside couldn't see.

[00:17:48]They could only hear the groan of the hull, the hiss of incoming water, the tick of instruments failing one by one.

[00:17:54]And they could feel the next charge coming, the splash above, the sinking sound as it fell through the water toward them, and then nothing. A fraction of a second of silence that felt like a lifetime. Then the world shook apart. Japan started the war with 63 oceangoing submarines. Over the next four years, they built 111 more. Of the total 174, 128 were lost. 75% of the 30 submarines that supported the attack on Pearl Harbor, not a single one survived the war. Each boat that went down took its entire crew with it. 80 men, 100 men, 140 men, no survivors, no wreckage, just a position on a chart where a submarine had last reported in and then silence.

[00:18:47]By mid 1944, the situation was beyond desperate. The American submarine campaign had strangled Japan's supply lines. Fuel was running out. Steel was scarce. The fleet could barely move. And the submarine force, once the pride of the Imperial Navy, was bleeding to death, one boat at a time in an ocean that had become a graveyard. It was in this atmosphere that two young officers proposed an idea that would have been unthinkable a year earlier. Their names were Lieutenant Kuroki Hiroshi and Lieutenant Nisha Seio. Both were submariners. Both understood torpedoes and both understood that the war was lost unless something changed. Their idea was simple in concept and horrifying in execution. Take a type 93 torpedo, the famous longlance, the most powerful torpedo in the world, and stretch it. Add a cockpit. Install a periscope, a set of rudimentary controls, and the canvas seat. Put a man inside. Aim it at a ship. Let the man steer. They called it kiten. It translates roughly as turn the tide of heaven. A more honest translation might have been, "We have run out of ideas and we have run out of hope. So, we will spend the only currency we have left, human lives." The concept had been rejected earlier in the war when Japan was winning. Now with defeat visible on every horizon, it was approved. Not purely for military reasons, the high command knew on some level that a man inside a torpedo was not significantly more effective than a torpedo by itself.

[00:20:25]It was approved because it echoed something the Navy wanted to believe about itself. It echoed the nine submariners who had died at Pearl Harbor. The ones who had been made into gods, the ones whose sacrifice, however futile, had been declared beautiful. The Kitan was about 48 ft long. It weighed 9 tons. Its warhead carried 3,400 lb of explosive, more than three times the payload of a standard torpedo. It could reach speeds of 30 knots. And it was, in the words of one historian, not so much a ship as the insertion of a human being into a very large torpedo. The pilots trained on a small island called Otsushima. They were between 17 and 28 years old. They practiced in shallow bays, first in sailboats, then in training kitons with dummy warheads and emergency surfacing mechanisms. They ran laps. They navigated obstacle courses.

[00:21:22]They attacked target ships in open water. More than 12 of them died in training accidents, including Kuroki himself. One of the two men who had invented the weapon. He was killed inside his kiten during an early test run. His co-inventor, Nisha, was left to carry the project and the grief alone.

[00:21:43]The technical reality of the kiten was far worse than the propaganda suggested.

[00:21:48]Sea water leaked into the cockpit whenever the mother submarine was submerged. This caused roughly 40% of all kitins to malfunction before they could even be launched. Their engines flooded their electrical systems, corroded their motors, catching fire from oil contamination. The periscope was nearly useless above 5 knots. Since the Kitan traveled at 30, the pilot was essentially blind for most of his final run. The controls were heavy and sluggish. The pilot had to manually adjust the water ballast by hand as fuel burned off. adding one more impossible task to a man already steering himself toward death at high speed in near total darkness. And perhaps worst of all, there was no communication between the Kitan and the mother submarine after launch. Once the pilot was released, he was alone. The crew aboard the submarine could only listen for an explosion and guess, and they almost always guessed wrong, wildly absurdly optimistic about results that in reality were almost non-existent. The mother submarines paid an additional price because kitans could not withstand water pressure below about 260 ft. Any submarine carrying them was restricted to shallow dives. This made them far easier for American anti-ubmarine forces to detect, track, and destroy. Carrying the weapon that was supposed to save the fleet was in practice a way of accelerating its destruction. Some Kaien pilots survived their missions returning to base after mechanical failures or aborted launches.

[00:23:24]This perversely was devastating. These were men who had written their final letters, who had given away their possessions, who had prayed at the small Shinto shrine aboard the submarine and prepared their spirits for death. Coming back alive was not relief. It was humiliation. It was failure in a culture that had made death the only acceptable outcome. On November 20th, 1944, the submarine I47 under Lieutenant Commander Orita Genji crept toward the American anchorage at Ulitatal deep in the Western Pacific.

[00:24:01]Strapped to her deck were four kitons.

[00:24:05]Inside the submarine, four young pilots gathered at the tiny Shinto shrine. They prayed. They left letters, poems, and keepsakes to be sent to their families.

[00:24:16]They wore dark jumpsuits, short ceremonial swords, and white silk headbands, hachimaki, emlazed with the rising sun. One of them was Nisha Seiko, the surviving co-inventor of the kiteen.

[00:24:28]In his hands, he carried a small white wooden box. Inside the box were the ashes of Kurroi Hiroshi, his partner, his friend, the man who had imagined this weapon into existence and then died inside it. Nisha was launched first. His kiten struck the fleet oiler USS Mississippi, a ship that had filled its tanks with nearly 17,000 cubic meters of aviation gasoline the day before. The explosion sent a column of flame 100 ft into the sky. 63 American sailors were killed. Beneath the waves aboard a different submarine, I36, the crew heard the detonation and erupted in celebration. Based on the size of the blast, they estimated they had sunk three aircraft carriers. They had sunk one oiler. At the same moment, hundreds of miles away, the submarine I37, also carrying kitons, was detected by two American destroyer escorts, USS Conklin and USS McCoy Reynolds. The destroyers attacked with hedgehog mortars. I37 went down with all 117 men aboard. Not a single kiton was launched. The final accounting of the first Kitan mission.

[00:25:42]All eight pilots dead. 117 submariners dead. One tanker sunk. 63 enemy sailors killed. The high command called it a success. While Nisha was dying at Uri Hashimoto Moitsura was just beginning his war aboard I-58. He had taken command of the submarine in May 1944 while it was still under construction at the Yokosuka Naval Arsenal. He supervised the fitting out drilled his crew relentlessly and watched as the boat was modified mid construction to carry kaithan a modification. His crew considered a great honor. Hashimoto was less convinced. He was a torpedo man. He had spent years studying the geometry of underwater attacks. The physics of the type 95, the mathematics of lead angles and closing speeds. He understood in his bones that a weapon you could aim precisely was worth more than a weapon you could not control after launch. The Kitan was the latter and the high command was obsessed with it. I-58 was commissioned on September 7th, 1944 and by late December she was loaded with four Kitans and their pilots heading for the Marana Islands as part of the Congo Group. six submarines, each carrying four kitons, targeting five American anchorages simultaneously. I-58 was assigned to Guam. In the early morning hours of January 12th, 1945, Hashimoto maneuvered to within 11 mi of the lighthouse at Opera Harbor. Between 3:10 and 3:27 in the morning, he launched all four kitons. One detonated immediately after launch, close enough to I-58 to force Hashimoto into an emergency dive.

[00:27:29]The others disappeared into the darkness. He saw two columns of smoke on the horizon as he pulled away. He could not determine what if anything had been hit. He could not contact the pilots. He could not verify results. He could only leave. This was the flaw Hashimoto had seen from the beginning. Without communication, without confirmation, the entire Kiteen program was built on guesswork and wishful thinking. He reported to headquarters that he had likely sunk an aircraft carrier and a large merchant ship. He had sunk neither. The pattern repeated.

[00:28:05]In March, I-58 was sent to support the fight at Evojima, but the mission was cancelled mid-transit. Hashimoto jettisoned two kitons to gain speed and was rerouted to serve as a radio relay station for a wave of kamicazi bombers heading for Uliti. Of 24 planes launched, only six reached the target.

[00:28:26]One managed to crash into the flight deck of the carrier USS Randolph. Then came Okinawa. In April 1945, I-58 was ordered to penetrate the massive American anti-ubmarine screen around the island and launch kitons against the invasion fleet in support of the battleship Yamato's own suicide run south. On April 7th, Hashimoto received word that Yamato had been sunk by American aircraft, taking over 4,000 men with her. For the next 8 days, I-58 tried to break through the American defenses. She was attacked by aircraft more than 50 times. She could never surface for more than a few hours, often only 10 minutes before lookout spotted incoming planes. The batteries drained, the air fouled, the crew weakened. I-58 became the only Japanese submarine to withdraw from the Okinawa operation alive. She limped into Kur on April 30th, 1945.

[00:29:27]She had not sunk a single ship at Kur.

[00:29:30]The mechanics removed I-58's aircraft catapult and hanger equipment. That was useless now since there were barely any aircraft left to fly and welded two more kiten shackles to the deck. The submarine could now carry six kitons instead of four. During the refit, American B29 bombers struck the port.

[00:29:50]I-58 was not hit, but other submarines were destroyed at their moorings.

[00:29:55]Hashimoto watched the fires and understood what every officer in the Imperial Navy already knew, but could not say aloud. The war was over. It had been over for months. What remained was not strategy, but ritual. The ritual of sending men out to die in machines that would accomplish nothing. Because the alternative was to admit that all the deaths that had come before had been meaningless. By July 1945, the Imperial Japanese Navy had fewer than a dozen submarines still capable of patrol. I-58 was one of them. On July 16th, she left Hi with six kitans strapped to her deck.

[00:30:35]She turned back almost immediately. The Kitan periscopes were defective and needed repair. 2 days later on July 18th, she departed again, threading through minefields around Kyushu, diving by day, surfacing at night, heading south and east toward the Philippine Sea. Hashimoto, now 36 years old, a veteran of Pearl Harbor, a man who had watched pilots crawl into steel tubes to die who had launched weapons he knew were useless, who had spent months underwater in a machine that had accomplished precisely nothing.

[00:31:11]Was heading out on what he understood would probably be his final patrol. He carried six gitans. He did not believe in 19 Type 95 torpedoes. he trusted completely and the growing certainty that none of it mattered anymore. He was wrong about that last part. In 11 days, Hashimoto Moitsura would fire the most consequential torpedo salvo of the Pacific War. And the target he would hit was carrying something that would end his world entirely. But he didn't know that yet. Nobody did. On July 28th, 1945, 2 days before the event that would define his life, Hashimoto spotted a merchant ship escorted by a destroyer.

[00:31:56]He launched two kitons. Both failed. The destroyer USS Lowry sustained minor damage from an explosion in the water, but nothing was sunk. I-58 was depth charged and driven deep.

[00:32:14]Hashimoto escaped by diving to 300 ft while rough seas scattered his oil slick. He reported to headquarters that he had probably sunk a tanker. He had not sunk anything. This was the rhythm of his war. Launch miss lie. Move on. By now, every Japanese submarine commander was doing it inflating results because the truth was unbearable and because the men in Tokyo needed to believe that the kiteans were working, that the sacrifice meant something that the dead had not died for nothing. But the truth didn't care what anyone needed. On the evening of July 29th, 1945, I-58 was running south on the surface 250 mi north of Palao. The sea was dark. A gibbus moon hung overhead a few days past full casting pale gray light across the water. Shortly before midnight, the navigation officer, Lieutenant Tanaka, spotted something on the horizon. A shape moving coming from the east.

[00:33:16]Hashimoto raised his binoculars. The silhouette was large two turrets after tall tower mast. He estimated the speed at 12 knots. The ship was not zigzagging. He identified it as an Idaho class battleship. He was wrong about that, but he was right about everything else. The ship was USS Indianapolis, a Portland class heavy cruiser. Captain Charles Butler McVey III commanding. She had 1,200 men aboard. 4 days earlier, she had completed one of the most important missions of the war, delivering enriched uranium and components for the atomic bomb Little Boy, to the island of Tinian. the weapon that would be dropped on Hiroshima in exactly one week. Indianapolis was now heading from Guam to Lee in the Philippines for training duty. She was unescorted.

[00:34:07]McVey had requested a destroyer escort and been denied. American intelligence through the Ultra program had intercepted radio transmissions identifying at least four Kitan carrying submarines in the area. This information classified top secret was not passed to McVey. He had been told there was possible submarine activity. He had not been told there were confirmed submarines directly in his path. McVey had been zigzagging during the day, but ceased after nightfall, citing poor visibility.

[00:34:38]A decision that was within his discretion understanding orders.

[00:34:43]Hashimoto did not care about any of this. He did not know what the ship was carrying. He did not know its name. He knew only that it was large, it was close and it was not zigzagging. He ordered I58 to dive.

[00:35:00]He also ordered one Kitan pilot petty officer first class Shiraaki Ichiro to man kiten number six as a backup. But Hashimoto had no intention of using it.

[00:35:11]Not tonight. Tonight for the first time in the war, he had a clean shot, a textbook setup. The kind of approach torpedo officers dream about. He would use his type 95s, the weapons he trusted, the weapons he had trained for since 1939. At approximately midnight, the exact time varies between sources by a few minutes depending on whether you use Japanese standard time or local time. Hashimoto gave the order. Six Type 95 torpedoes left the bow tubes at 2-cond intervals. Each one weighed nearly two tons. Each carried over 1,000 lb of explosive. Each ran wakeless beneath the surface at 46 knots, invisible, silent, and unstoppable.

[00:36:00]Hashimoto pressed his eye to the periscope. He counted the seconds. Then he saw two flashes equally spaced erupting against the ship's starboard side. One forward, one amid ships. The ship shuddered, slowed, began to list.

[00:36:16]He ordered I-58 into a deep dive 100 ft, fearing detection. The crew reloaded torpedo tubes in near darkness, working by feel hands, slick with oil and sweat.

[00:36:27]After an hour, Hashimoto brought the submarine back to periscope depth. The ship was gone. There was nothing on the surface, no wreckage visible, no fire, just empty ocean under moonlight.

[00:36:40]Indianapolis had capsized and sunk in 12 minutes. Approximately 300 men went down with the ship trapped below decks, killed by the explosions drowned in flooded compartments. About 900 made it into the water. They had almost nothing.

[00:36:57]A few life rafts, some carpok life vests, no food, no water, no radio. The ship had sunk too fast for a reliable distress signal to be sent or acknowledged. The men floated. They clustered in groups. They held on to each other and to whatever debris they could find. The sun rose. The Pacific stretched in every direction. Flat blue, infinite, and indifferent. And then the sharks came. They came in ones and twos.

[00:37:25]At first drawn by the blood and oil in the water, then in larger numbers.

[00:37:30]Oceanic white tips, the open water predator. The species that has killed more humans than any other. They circled, they bumped, and then they attacked. Men were pulled under without warning. The water turned red, then brown, then clear again. The survivors who witnessed it could do nothing. They screamed. They kicked. They splashed.

[00:37:54]Some went silent and simply stared. The Navy did not know Indianapolis had sunk.

[00:38:00]The ship had not been listed as expected at Leech. A receiving station that picked up a distress call didn't act because the commanding officer was drunk. Another dismissed it as a Japanese trap. A third officer had given orders not to be disturbed. The bureaucratic failures stacked on top of each other like sediment. Each one adding another hour another day to the time those men spent dying in the water.

[00:38:27]On August 2nd, 4 days after the sinking, Latutenant Wilbur Gwyn flying a routine patrol in a PV1 Ventura out of Pelleu noticed an oil slick on the surface. He dropped lower. He saw men, dozens of them, maybe more. He radioed his base.

[00:38:47]The Navy wasted 3 hours questioning whether it was possible that a ship's crew was floating in the ocean.

[00:38:53]Lieutenant Adrien Marx, a pilot from Indiana, was dispatched in a PBY 5A Catalina sea plane to observe and report. He was under strict orders not to attempt an open sea landing. When he arrived and looked down, he saw men being attacked by sharks in real time.

[00:39:10]He pulled his crew. They agreed. He landed anyway, setting the Catalina down in 12t swells, popping rivets on impact.

[00:39:19]His crew began pulling survivors from the water. When the plane was full, they tied men to the wings with parachute cord. By nightfall, Marx had rescued 56 men. The destroyer USS Ceil J. Doyle arrived later that evening. Her captain, against standing orders, turned on the ship search light. A beacon visible for miles in every direction, risking attack from any Japanese vessel or aircraft in the area. He did it because men in the water needed to see that help had come.

[00:39:50]Of the roughly 900 men who had survived the sinking, 316 were pulled from the sea alive. Four more died after rescue.

[00:39:59]The final count 879 dead. It was and remains the greatest single loss of life at sea from a single ship in the history of the United States Navy. I-58 continued her patrol. On August 7th, her radio operators intercepted transmissions about the atomic bombing of Hiroshima. Hashimoto did not fully understand what had happened. He kept hunting. On August 9th, he launched two more kitons against a convoy near Luzon.

[00:40:27]They were destroyed by the destroyer escort, USS Johnny Hutchkins. On August 12th, he launched his last kitons, also destroyed. On August 15th, I-58 surfaced in Bango Strait, and Hashimoto heard the Emperor's broadcast announcing Japan's surrender.

[00:40:47]He brought the submarine up the inland sea to Hiao. He gathered his crew on deck and told them the war was over.

[00:40:54]After the war, it was confirmed USS Indianapolis was the only ship I58 had ever sunk. It was the last significant Japanese naval success of the entire war. And then Hashimoto went home. What he found when he got there, or rather what he did not find, is where the story becomes something else entirely.

[00:41:16]Something that sits beyond the reach of military history and enters the territory of private grief so vast it can only be called fate's crualist arithmetic. His family had been in Hiroshima. The atomic bomb little boy had been dropped on August 6th, 1945.

[00:41:33]The weapon whose components had been carried across the Pacific by USS Indianapolis. The ship Hashimoto had sunk on July 30th. The ship that had completed its delivery on July 26th, 4 days before he found it, he had not stopped the bomb. He could not have stopped the bomb. The delivery was already complete. But the symmetry was inescapable.

[00:41:57]The man who sank the ship and the bomb the ship had carried, they had destroyed each other's worlds unknowing across the same ocean in the same week. Different sources describe the loss differently.

[00:42:09]Some say his entire family was killed.

[00:42:12]Others say most of his family. What is certain is this Hashimoto was devastated. And a daughter Sonoi was born in 1947, suggesting that at some point after the war, he began again.

[00:42:25]There was one more act. In November 1945, Captain Charles McVey, the man who had commanded Indianapolis, was court marshaled. He was charged with failing to zigzag and hazarding his ship. It was the only court marshal in the history of the United States Navy for a captain who lost his ship to enemy action. Roughly 380 American warships had been sunk in combat during the war. McVey was the only commander prosecuted. Hashimoto was brought to Washington to testify for the prosecution. An armed escort flew to Japan and delivered him to the capital.

[00:43:02]It was the first time an officer of a nation at war with the United States had testified against an American officer in a court marshal. The courtroom was packed. The press was hostile. And Hashimoto, speaking through a translator, having taken oaths under both Japanese civil law and US Navy regulations, said something the prosecution did not want to hear. He said the visibility that night was fair.

[00:43:27]He said he had spotted Indianapolis easily and he said clearly without hesitation that zigzagging would not have made a difference. His position was too favorable. He would have sunk the ship regardless. McVey was convicted anyway. The conviction effectively ended his career. He was restored to duty but never given another command at sea. He retired in 1949 with a promotion to Rear Admiral, a hollow gesture. For years, families of the Indianapolis dead sent him letters. Some were messages of grief. Some were accusations. Some were threats. His wife died of cancer in 1961.

[00:44:08]After that, the loneliness closed in. On November the 6th, 1968, Charles Butler McVey III, 70 years old, took his own life at his home in Lichfield, Connecticut. His gardener found him on the back porch the next morning. He had been alone for a long time. Hashimoto lived. After the war, he commanded repatriation ships, bringing Japanese soldiers home from across the Pacific.

[00:44:33]He joined Kawasaki Heavy Industries and became a dockmaster.

[00:44:38]In a strange twist, he and several former crew mates from I-58 helped test the Oashio, the first submarine built by Japan's postwar Maritime Self-Defense Force. The man who had spent the war inside a submarine that never sank a ship until the very end was now helping to build the submarine force of a new Japan. And then in his final years, Hashimoto did something no one perhaps not even he could have predicted. He became a Shinto priest. He served at Umomia Taisha, a shrine in the western hills of Kyoto dedicated to plum blossoms and safe child birth. founded over a thousand years ago. The same shrine where his father had served. The same shrine where he had been born. The son who left for the sea had come home.

[00:45:26]In December 1990, Hashimoto traveled to Pearl Harbor, not as a naval officer, not as a warrior, as a pilgrim. He came to meet the surviving crew members of the USS Indianapolis, the men who had floated in sharkinfested water for 4 days because of the torpedoes he had fired. He stood before them an old man now 81 years old speaking through a translator and said seven words that no amount of military doctrine or national pride could have prepared him for. I came here to pray with you for your shipmates whose deaths I caused. A survivor named Giles McCoy looked at the man who had sunk his ship who had killed his friends who had sent him into four days of hell in the open Pacific Ocean.

[00:46:11]McCoy said three words. I forgive you.

[00:46:14]In 1999, Hashimoto wrote a letter to the United States Senate Armed Services Committee. He was 90 years old. The letter was about McVey, the captain whose life had been destroyed by the court marshal, the man who had been dead for 31 years. Hashimoto wrote that zigzagging would not have saved Indianapolis. He had said this in 1945.

[00:46:37]He said it again now. And then he wrote something else. Something that went beyond torpedo trajectories and naval tactics and entered the space where enemies become something harder to name.

[00:46:50]Our peoples have forgiven each other for that terrible war and its consequences.

[00:46:56]Perhaps it is time your peoples forgave Captain McVey for the humiliation of his unjust conviction. The enemy commander asking America to forgive its own captain. Hashimoto Mochitsura died on October 25th, 2000. He was 91 years old.

[00:47:15]5 days later, on October 30th, 2000, the United States Congress passed a resolution exonerating Captain McVey.

[00:47:23]President Clinton signed it. McVeyy's record was amended. The conviction was acknowledged as unjust. Hashimoto never knew. He died 5 days too soon. And what of Sakamaki Kazou? the young enen whose departure Hashimoto had watched from the deck of I24 on the morning of Pearl Harbor. The man who had been erased from Japanese records for the crime of surviving. Sakamaki spent the war in American prisoner camps. He returned to Japan a pacifist. He joined Toyota Motor Corporation Learned English and rose through the ranks. He became president of Toyota's Brazilian subsidiary. He built a quiet, successful life, a life defined not by how he had failed to die, but by how he chose to live. In 1991, Sakamaki visited the National Museum of the Pacific War in Fredericksburg, Texas. His submarine HA19, the tiny vessel that had carried him into Pearl Harbor 50 years earlier, was on permanent display. He stood in front of it and he wept. He died in 1999.

[00:48:34]He was 81 years old. He had outlived almost every man the Imperial Japanese Navy had ever called a hero. The man they had erased for living was the one who endured the longest. On April 1st, 1946, the submarine I-58, stripped of all equipment emptied of everything useful, was towed from SASBO to an area off the Gooto Islands by the submarine tender USS Narius. Demolition charges were set. She was blown up and sank in 660 ft of water. In May 2017, a sonar survey detected her remains on the seafloor. A 60 m section of hull standing perfectly vertical in the darkness 200 m down like a headstone.

[00:49:20]The priest's son who went to sea. The submarine that couldn't sink anything until it sank the wrong ship at the wrong time and changed the mathematics of grief for two nations. The pilots who climbed into steel tubes to die for an empire that was already dead. The captain who was punished for being torpedoed. The prisoner of war who was punished for surviving. The old man at the shrine praying for the men he killed. None of them asked for absolution from history. History doesn't give it. But forgiveness that came from somewhere else, from a man floating in sharkinfested water who looked at the man who put him there and said the only words that mattered. I forgive you. That is where this story ends. Not in the ocean, not in the fire, in the space between two men who had every reason to hate each other and chose not