Operation Storm: Japan's Top Secret Submarines and Its Plan to Change the Course of World War II

by John Geoghegan

  Warning Nambu to “refrain from any rash or irresponsible actions until the crew had returned home,” Ariizumi concluded by promising to watch over the reconstruction of Japan from his resting place in the Pacific.15

  Ariizumi’s note to his wife was written in the third person and further explained the reason for his death. “Ariizumi is sorry from the bottom of his heart for losing the war,” he penned. He finished with a farewell poem outlining his hopes for their family:

  May our children grow up to be pure of heart / And be strong and just to benefit the world.16

  They hardly seemed the words of a murderer.

  The I-401 was the world’s largest sub, but it was a small boat when it came to gossip. Word that the commander had killed himself spread quickly.17 Nambu was particularly concerned about the Segundo’s reaction. If the Americans learned that Ariizumi had killed himself, they might treat his body disrespectfully. Therefore, Nambu decided not to inform them of Ariizumi’s death and to secretly bury his commander at sea.18

  While the I-401’s medical officer filled out a death certificate, Nambu and Bando covered the commander’s body in a blanket.19 Next they wrapped him tightly in a Japanese naval ensign,20 its 16 rays matching the number of petals on the emperor’s chrysanthemum seal. When they were finished, they changed into formal naval dress.21 Meanwhile, one of the Seiran mechanics made an ossuary box, using wood from a shoji game board, for presentation to Ariizumi’s family.22

  It took several men pushing and pulling to get the commander through the number-two deck hatch. Though Ariizumi had lost weight, he was still stout.23 Keeping his voice low to avoid alerting the prize crew, Nambu presided over a brief funeral ceremony. When it was over, they saluted their commander one last time before silently committing his body to the sea. A weighted bag ensured he sank to the bottom.24

  By the time Nambu finished his silent prayer, the sun was coming up. Though Ariizumi’s burial was without benefit of sutra or song, it had been a warrior’s funeral nonetheless.* 25 He had died as he had lived: fierce, unwavering, and committed to his principles. His decision to kill himself must not have been easy, but it was consistent with the values he professed and the honor he passionately embraced. Commander, mentor, loyal subject, faithful officer, father, husband, butcher, friend—Ariizumi had been all these things and more. He’d earned the respect of his men as well as their fear and had fought as valiantly as any officer in the Imperial Japanese Navy. Now he was gone to rest at the bottom of the sea. But who would forgive him his crimes?

  LIEUTENANT BALSON ORDERED Carlucci to lower the I-401’s naval ensign and raise the American flag at 5:00 A.M. Carlucci knew it was a slap in the face to the Japanese,26 and he performed his task with relish. Though the ceremony was largely symbolic, it meant the I-401 was no longer a Japanese sub—she was officially an American war prize.

  With Mount Fuji in the background, Nambu watched as the flags were exchanged, chafing at the sight.27 Bando wasn’t about to let the Japanese naval ensign fall into enemy hands, so when the flag came down, he secretly ordered the signal officer to burn it.28

  The I-401 wasn’t ready to concede, even in surrender.

  * The crew of the USS Segundo did in fact observe Nambu’s deck gathering. When Captain Johnson demanded to know what was going on, he was told the Sen-toku’s squadron commander had committed suicide. Johnson doubted the truth of the statement, since he wasn’t even aware Ariizumi had been on board the sub.

  CHAPTER 40

  BITTERSWEET

  WHEN THE CREW OF THE SUBMARINE TENDER PROTEUS SAW THE I-401 approach, they began cheering with all their might.

  “Wonderful! Big one!” they cried.

  Yata, the I-401’s gunnery officer, was proud his sub caused a commotion. After all, it was the the Sen-toku squadron’s flagship, it was only right that the Americans found her impressive.1 But Nambu’s sub almost hadn’t made it to Tokyo Bay. The Segundo had been escorting the I-401 when Johnson received orders to immediately reverse course and take her back to Sagami-wan. Adm. William “Bull” Halsey had received reports from Japanese naval officers that the I-401 was dangerous and that U.S. ships should avoid her at all costs. Since Johnson had also reported the I-401 as hostile and Lieutenant Balson felt the situation was not well in hand,2 Halsey didn’t want the rogue sub anywhere near his Third Fleet.

  Of course, Nambu had no intention of resisting. As a sign of compliance, he’d presented Balson with his service sword at 11:00 A.M., turning over command exactly as promised. Balson informed the Segundo that the “formal surrender had been received.”3 By then, it was too late. The USS Gatling (DD-671) and USS O’Bannon (DD-450) had already arrived. Sent as a show of force, the Fletcher-class destroyers had orders to escort a compliant I-401 into Tokyo Bay or blast her out of the water. With Ariizumi dead, all Nambu wanted was to return his men to Japan. Unfortunately, no one believed his good intentions after the sub’s previous recalcitrance. At a time when things should have been settling down, they were heating up all over again.

  Sagami Bay was crowded with Third Fleet ships, each a tempting target if Nambu had wanted to ram one. U.S. naval officials remained concerned right up to the point when the I-401 docked near the Proteus. But Nambu was a man of his word. He maneuvered alongside the giant American sub tender without incident.

  The biggest surprise for Nambu’s crew was finding the I-400 already there. There was sadness amid the joy, however. Both the I-13 and the I-14 were absent. When Takahashi tried asking the I-401’s crew about the missing subs, he was stopped by American MPs.4 The I-14 arrived shortly thereafter,5 but the I-13, a casualty of war, would never return home.

  The Sen-toku subs proved to be a popular attraction. Over the next few days, they were visited by a bevy of navy brass, including Halsey and Lockwood. Lockwood was present for the I-400’s arrival. When he boarded her for inspection, he immediately noticed the “lousy appearance of the enemy crew.”

  “Normally, a Jap is clean,” Lockwood observed. “These were filthy in clothing and person.”6

  Sen-toku crews also lamented the condition of their maintenance-deferred subs. When compared to the spic-and-span standards of Allied ships, they made a poor showing.7 Even Asamura noticed the difference. Considering the almost unlimited supply of paint they were given to refresh the I-401, Asamura concluded the United States must be a truly rich nation.8

  The true purpose of the underwater aircraft carriers remained hidden, at least for a while. Lockwood was under the impression that the I-400 had been on a supply trip to Truk. He also couldn’t understand why Captain Kusaka hadn’t seen any American warships en route.9 Of course, the answer was clear—Kusaka was lying. Though Kusaka had spoken honestly when he’d said the I-400 had never sunk an Allied ship, he’d most certainly seen them. Though it was easy to mistake the I-400’s airplane hangar for a warehouse, especially since the planes had been replaced with supplies, it’s surprising that the commander of Pacific Fleet subs didn’t learn of Kusaka’s mission until later. Unless the Japanese were launching food at captured islands, there was no reason for a catapult other than for aircraft. It’s hard to imagine how anyone bought the story that the I-400 was a cargo sub.

  Not surprisingly, U.S. sailors didn’t just want to see the world’s largest submarines—they wanted to take a piece home with them. The I-401’s medical officer was so concerned that the wardroom’s Japanese doll would be stolen that he burned it.* 10 Nevertheless, American sailors proved innovative scavengers. Swords and sidearms were first to go, but items necessary to the operation of the sub, including the I-401’s chronometer, compass, barometer, and binoculars, soon followed. It goes without saying that any sake or scotch that was discovered also disappeared.11 Later choices were of more dubious value. When the crew’s personal razors went missing, it redefined the meaning of acceptable war booty.12

  A cease-and-desist order was issued before things got out of hand.13 This wasn’t done so much to protect the personal belongings
of Japanese POWs as to ensure that the good stuff wasn’t looted before higher-ups got their chance. The I-401’s sidearms and service swords were eventually distributed according to rank, but even Balson wasn’t able to hold on to Nambu’s service sword for more than a few hours. As soon as Lew Parks, commander of SubRon 20, saw it, he took it for himself.14

  Not all the pillaging happened without consequence, as Hi Cassedy soon learned. Quick to confiscate the I-400’s service swords, he had planned to personally redistribute them. When Halsey got wind of it, Cassedy became the highest-ranking officer to fall afoul of souvenir fever. Though Cassedy wasn’t in the doghouse long, it must have given the Blue’s skipper some satisfaction to know that Cassedy was the only U.S. officer ever relieved of command of a Japanese sub.15 Still, it didn’t slow the stripping of the Sen-toku subs.

  There were generous acts amid the looting. After their arrival in Yokosuka, Johnson gave Bando his Zippo lighter and invited the chief navigator to visit him in the United States after the war.16 Bando still remembered the kindness 65 years later, suggesting that Johnson could build bridges, not just destroy them.

  In fact, many of the Segundo’s crew had to admit they’d been wrong about Johnson. No matter what their concerns had been at the beginning of the patrol, there was no denying that he had handled himself well. He’d shown surprising restraint while chasing an unknown sub for four hours, and foresight by consulting with ComSubPac before taking action. Furthermore, he had remained calm during negotiations with a wily enemy, despite mixed signals. He’d been tough when necessary, insisting on escorting the I-401 to Yokosuka; flexible when it came to Japanese face saving. Another skipper might have plunged them into a shooting war, but Johnson had shown grace under pressure while never letting his guard down. In other words, Stephen Lobdell Johnson had achieved something very important for a sub captain: he’d earned the respect of his crew.

  LOCKWOOD MAY HAVE DESCRIBED Ariizumi’s suicide as “the happy event,”17 but it was not so for everyone. The commander’s family was devastated. Matsu was every bit as much a product of the Imperial Japanese Navy as her husband. She had lived within its strictures and was proud of his success. He had not only become one of the navy’s most trusted operational officers, he had done so while remaining true to his creed. Now he was gone, dead by his own hand. Yet by sacrificing himself, he’d brought honor to his family.

  As much as Matsu grieved for her husband, she knew he had done the right thing. Now she resolved to join him. Just as the 47 Ronin had killed themselves after avenging their master’s death, Matsu would make the ultimate sacrifice and follow in her husband’s footsteps. Even though the Japan she had grown up with now lay in ruins, Matsu would uphold tradition.

  For not only was Matsu going to end her own life—she was going to take the lives of her five children as well. It was a horrific decision for a mother to make, but in her mind, it was the only choice she had left.

  * According to Kazuo Nishijima, Kusaka gave a similar doll, as a token of friendship, to the U.S. officers of the I-400’s prize crew. When it was accidentally broken, Cassedy yelled at his officers for their rough treatment. However, one of the I-400’s crewmen felt sympathy for the Americans and repaired the doll for them.

  CHAPTER 41

  FREEDOM

  THE I-401’S COMMUNICATIONS CHIEF, LT. (SG) GOICHI KATAYAMA, brought Matsu her husband’s suicide note.1 He’d served aboard the I-8 with Ariizumi and felt close to the commander. The note expressed Ariizumi’s wish for a better life for his children, but Matsu could not ignore the fact that her husband had killed himself.

  It was not unusual for a wife to follow her husband in suicide, especially in a feudal structure like the Imperial Japanese Navy. Wives had been following their husbands’ example for centuries in Japan, and Matsu wasn’t just a navy wife—her husband was an Etajima graduate, had served on the Naval General Staff, and had commanded the last submarine squadron of the Great Pacific War. Matsu was a role model for many, her actions studied and critiqued. The psychological pressure must have been enormous.

  Still, she faced a dilemma. If Matsu and her children died, no one would be left to carry on the family line. Children were necessary to venerate the memories of their parents and ancestors, so it was crucial that the family bloodline be continued. And so Matsu chose to spare her oldest son, Nobukazu, and her younger daughter, Yasuko. Her remaining three children would follow her into death.

  When the fateful day arrived, Matsu gathered her elder daughter, Shizuko, and her second and third sons, Keisuke and Yosuke. Matsu had told no one about her decision save her mother, who waited quietly in the next room. The house remained dark in the shade of its garden, and the tatami mat floor muffled the small footsteps as the children gathered round.

  Matsu used her cheeriest, high-pitched voice to address her children. Her message was honest if veiled.

  “Let’s go join your father.”

  But Keisuke, a chipper boy of four, was hungry.

  “Not until we’ve eaten all the delicious things in our house, Mother.”

  “Of course, let us eat it all,” she said choking back tears.

  After a moment, Keisuke added, “Let’s be sure to eat the persimmons too, Mother.”

  “Of course, the persimmons and the chestnuts,” Matsu responded, for she knew the chestnut tree, which had been planted in their garden by Ariizumi’s father, had borne fruit for the first time that season.

  Before Matsu could make good on her promise though, Keisuke had one last question.

  “Mother, the persimmons will grow again next year, won’t they?”

  Matsu’s mother, who had been listening, was overwhelmed by the innocent question. The thought of this tiny child’s death was too much to bear. Yes, their persimmon tree would bloom next year, but her grandson would not. Struggling with emotion, she interrupted the gathering.

  “Death is not the only way to serve [your husband],” she said, tears in her eyes. “Please do not die.”2

  Matsu must have felt terrible as her mother’s plea echoed in her ears. Sacrificing her children in the name of honor went against every maternal instinct. And yet she was the dutiful wife of a senior naval officer. She knew what she must do.

  As her mother’s sobbing filled the room, Matsu considered her family’s fate. Her youngest son was but an infant, Keisuke no more than a toddler. Must she really sacrifice their lives to preserve the family honor? Or had Japan changed enough that her children might be spared?

  Whatever else transpired in the Ariizumi house that day, Matsu decided that she and her children would survive. They would not follow her husband into death. They would live to taste persimmons another year.

  SEPTEMBER 2, THE day the Japanese signed the Instrument of Surrender, was Lockwood’s day in the sun. Twelve U.S. fleet subs, including the Segundo, were invited to participate in the ceremony and anchored in a nest alongside the Proteus in Tokyo Bay. Lockwood’s personal three-star flag hung from the I-400’s bridge during the ceremony. Though he later admitted he was “gloating … over the enemy,” Lockwood was proud of what he’d achieved.3 One still has to wonder whether the commander of the Pacific sub force understood that he’d chosen the lesser of two submarines to gloat over. The real prize was Ariizumi’s flagship, the I-401.

  The next day the Segundo departed Tokyo for Pearl Harbor. It took a week to reach her destination. When the sub arrived, her crew was in for one last surprise. While the Segundo was in dry dock for inspection, a large dent was found in her starboard hull. A closer look revealed a yellow smear between the forward and aft engine compartments, most likely from the warhead of an enemy torpedo.4

  Wallace Karnes remembered the bump they’d heard while approaching Sagami Bay and drew the simplest conclusion. “One of the I-401’s buddies must have snuck up and torpedoed us,” he said. “That was funny.”5

  Funny in retrospect, maybe. But if the torpedo, depth charge, or sea mine hadn’t been a dud, the Segundo’s la
st war patrol could have had a very different ending.

  ONCE THE JAPANESE surrender was official, learning how to operate the I-400 subs became the next order of business. All the subs’ manuals, schematics, and diagrams had been thrown overboard, which meant U.S. submariners had to learn from scratch. Though Japanese sub design followed standard practice,6 there was still a bewildering array of pipes, valves, dials, and switches to decipher. Turn the wrong valve, and you might flood the sub. It was time to learn how these monsters worked.

  Japanese petty officers proved crucial to explaining how the subs operated.7 They walked every inch of the surviving Sen-toku squadron with U.S. submariners in tow.8 Ironically, the jailers soon learned that their prisoners were demanding taskmasters. U.S. prize crews produced drawings of every aspect of each sub’s layout and systems. A Japanese-English dictionary of submarine terms also took shape. It proved helpful in understanding the strange Japanese markings that appeared everywhere. Most terms were new to the American submariners, but there was the occasional amusing display of English without l’s—for example, barasuto tanku for “ballast tank.”9

  As the prize crews grew more confident, they began entertaining visitors with demonstrations of the sub’s catapult, raising and lowering her hydraulic crane, and opening her hangar door.10 The Japanese petty officers were surprised at how fast the Americans caught on. Despite the language barrier, the learning process went quickly. After a week of training, Cdr. Joseph M. McDowell was ready to take the I-400 out for sea trials—proof that submariners spoke the same language regardless of the country they came from.

  THOUGH NAMBU RECEIVED “gentle treatment by the U.S. Navy,”11 Sen-toku officers faced extensive questioning by naval intelligence. At first investigators wanted to know which ships Nambu had sunk, but they soon zeroed in on who had served in the Indian Ocean. Clearly, the Allies knew about the atrocities and wanted to find out which subs were involved.