Operation Storm: Japan's Top Secret Submarines and Its Plan to Change the Course of World War II (29 page)

The joint army-navy undertaking was named Operation PX. Ishii recommended that aircraft drop fleas infected with bubonic plague, something he’d already tested with some success in China. Several cities were considered as targets, including San Diego, Los Angeles, and San Francisco. One source suggests east coast cities might have been considered as well.
²⁷

The navy approved Operation PX in early March 1945.
²⁸
Ariizumi was probably unaware of the change, since target selection was the provenance of naval higher-ups. Meanwhile, he continued preparing for the Panama Canal attack.

Approval was only momentary, however. In a March 26 meeting to discuss the operation, one of the army’s most senior officers, Yoshijiro Umezu, chief of the Imperial Japanese Army General Staff, rejected the plan.

“The operation is unpardonable on humanitarian grounds,” Umezu declared. “If a virus is used, war between Japan and the U.S. will escalate to war against all humanity and Japan will be the subject of derision.”
²⁹

Naval authorities opposed Umezu’s decision,
³⁰
but once the army had withdrawn its support, there was nothing they could do. Operation PX was killed before the
Sen-toku
squadron was any the wiser.

Given their respective historical roles, it’s ironic that the Imperial Japanese Navy proposed such an Armageddon-like attack while the army counseled restraint. Obviously, fighting had become so desperate there was nothing Japan wouldn’t do to prevent defeat. Though the navy had its share of harebrained schemes, including swimming tanks; human torpedoes; rocket-powered suicide planes; and some might even add the
Sen-toku
subs, the navy usually took a conservative path. But by 1945, Japan’s strategy of choice was to mobilize every means possible to resist surrender. If this meant organizing suicide attacks by
kamikaze
and
kaiten
, or
training women and children to use bamboo spears to repel an Allied invasion, so be it. Operation PX fit right into this mindset.

B
Y THE START
of 1945, the Sixth Fleet was a shadow of its former self. Only 20 modern combat subs were left, including the
Sen-toku
squadron. Many of the remaining subs were being refitted to carry
kaiten
, which meant combat subs were no longer considered offensive weapons as much as transport vessels for suicide torpedoes. Add to this a few surviving cargo subs and obsolete boats suitable only for training, and the Sixth Fleet was virtually extinct.
³¹

Nambu’s former command, the
I-362
, soon joined the list. The cargo-carrying sub had been scheduled to arrive at Mereyon Island on January 21. When she was reported missing, Nambu had no choice but to mourn his comrades.
³²
And the
I-362
wasn’t the only sub missing. Ariizumi’s Indian Ocean boat, the I-8, had been lost as well. The
I-8
had been pursuing an American convoy on the surface southeast of Okinawa
³³
when a lookout sighted the USS
Stockton
(DD-646). Part of the convoy’s screen, the U.S. destroyer tried contacting the Japanese sub using a megaphone.
³⁴
Ariizumi’s replacement, Lt. Cdr. Shigeo Shinohara, had no interest in listening, and ordered a crash dive.

As the
I-8
approached the 100-foot mark, depth charges began exploding near her stern.
³⁵
Since the
Stockton
easily determined the sub’s position from the sound of her propellers, the accuracy of the attacks improved and their frequency increased. Minutes later a depth charge exploded, holing the crew’s quarters, and water began flooding the compartment. The sudden loss of buoyancy forced the sub down near the 450-foot mark, dangerously close to crush depth. The cascading seawater concentrated in the sub’s stern exacerbated her plunge and tipped her bow upward at a 25-degree angle.
³⁶
It was like climbing the Matterhorn for anyone inside.

The crew did their best to make repairs, but the sub’s main power plant was offline, and the concentration of water in the
stern meant the sub continued to sink. The only thing Shinohara could do was give the order to blow the after tanks. Though this stopped the sub from imploding, the air bubbles betrayed her position, causing the
Stockton
to send down another wave of depth charges.
³⁷

The attack lasted four hours. All the
I-8
’s crew could do was silently await death.
³⁸
The
Stockton
made seven attacks in all. When her depth charges were exhausted, she was joined by the USS
Morrison
(DD-560), which dropped 11 more patterns.
³⁹
Finally, Captain Shinohara gave the order for battle surface. It was a brave if desperate move, because the
I-8
had no more torpedoes left with which to defend herself.
⁴⁰
The only thing Shinohara could count on was darkness. After the
I-8
blew her tanks, another mass of bubbles rushed to the surface, marking her location. When she broke the waves at 2:00
A.M.
, the enemy was waiting.

The
I-8
’s gun crew crowded into the conning tower while the sub cleared the waves. The moment the bridge hatch opened, the men sprang into action. There was a strong wind and a big swell as Petty Officer Takamasa Mukai ran barefoot to his station. The moon hung in the sky like a pale searchlight while Mukai loaded the 140mm gun.
⁴¹

The
Morrison
was only 900 yards away when the
I-8
surfaced. The destroyer spotted the sub off her starboard bow and immediately tried to ram her.
⁴²
The
I-8
’s 25mm antiaircraft gun was first to open up.
⁴³
Mukai also got a round off before enemy gunfire began smacking into the deck around him.
⁴⁴
A moment later a metal splinter pierced his foot.

Mukai ran to the bridge for help, but just as he approached, one of the enemy’s five-inch shells blew it apart.
⁴⁵
Stumbling back to his post, he resolved to make a stand. The two destroyers pounded the sub for half an hour.
⁴⁶
Finally, after multiple hits
⁴⁷
the
I-8
rolled over
⁴⁸
and went down by the stern. Mukai was thrown into the ocean. When he awoke, he found himself in the sick bay of an American destroyer,
⁴⁹
the only
I-8
crewman to survive.

These were but two examples of the fate that awaited the fast-dwindling number of Sixth Fleet submarines. Lost sub commands,
inexperienced flight officers, harsh water landings, and sandy hydraulic fluid were only some of the problems bedeviling the
Sen-toku
subs. Vice Adm. Marc A. Mitscher was about to significantly add to them. This time it was Kure’s turn to feel the pain.

K
URE WAS A
navy town. The IJN had been there more than a hundred years, bringing a measure of culture and sophistication to what otherwise would have been a sleepy little fishing village. Now one of Japan’s “big eight” cities, Kure was home to approximately half a million people, many of them connected with the IJN. Navy paychecks had enabled music, theater, and the tea ceremony to flourish, in addition to bringing running water and flush toilets to the city.
⁵⁰
The most important aspect about Kure was that it was home base to the principal units of the Japanese fleet. This made it a tempting target for Vice Adm. Marc A. Mitscher’s Task Force 58. Suddenly, it was payback time for all those islands America had wrested from Japan.

The
I-400, I-401
, and
I-13
were anchored at the Kure Naval Base when dawn broke the morning of Monday, March 19. The
I-401
’s crew had just returned from a five-day pass. Chin-Ji Inouye, the
I-401
’s sonar operator, was eating breakfast and thinking about his family when the air raid sounded. Sprinting to the
I-401
, he took up a defensive position alongside his crewmates. Time stood still as they craned their necks toward the empty sky. As sirens wailed in the background, they nervously awaited the arrival of the enemy air armada.
⁵¹

Satoru Fukuoka, a
Seiran
ground crew member, was carrying ammo to an antiaircraft battery halfway up a mountainside when American aircraft first appeared. As he watched the enemy’s attack leader dip his wing, Fukuoka prepared for the worst. One Grumman Hellcat after another swooped down in a power dive and, leveling out a few feet above the naval base, opened up with their 20mm cannons. The effect was devastating.
⁵²

Fukuoka’s AA battery found it difficult to shoot down the enemy
planes. The mountains shielded the aircraft until the last possible moment, and once their power dive began, it was too late.

Lt. Tsugio Yata, the
I-401
’s 22-year-old chief gunnery officer, had joined the sub just before her commissioning. An Etajima graduate, Yata was young and energetic but had never experienced battle.
⁵³
The attack happened so quickly, he had little time to organize the
I-401
’s defenses. As Helldivers and Corsairs began diving out of the sky, Nambu guided his gunnery officer: “Wait, wait, not yet, gunnery chief.” Then: “Now
Teppo
! Shoot!”
⁵⁴

The roar of the
I-401
’s triple-mount antiaircraft guns was so great, Yata couldn’t hear his own commands. His gun crew discharged at least 10,000 rounds defending their sub, but the enemy planes were so thick, it was like shooting a swarm of bees.
⁵⁵

The
I-400
was nearby in number-two dry dock and unable to move.
⁵⁶
The crew had been warned of the attack, so her guns were manned and ready when the first planes appeared
⁵⁷
at 7:30
A.M.
⁵⁸
Though trapped, she put up a good fight. Koshimoto, one of her many engineers, lugged ammo as fast as the gun crew could expend it.
⁵⁹
Brass casings piled on deck like New Year’s confetti, their delicate clinking lost in the cacophony.
⁶⁰
One enemy aircraft scribbled a smoke trail across the sky before exploding in midair.
⁶¹
Another lost a wing and turned upside down before crashing nearby.
⁶²
Although a few planes were shot down, it was the IJN that took a beating that day. U.S. aircraft were targeting four battleships anchored in the harbor:
⁶³
the
Yamato, Ise, Haruna
, and
Hyuga
.
⁶⁴
Normally, a battleship would try to escape an air attack, but that wasn’t possible in this situation—their fuel tanks were empty.
⁶⁵
Nevertheless, the battleships fought back with everything they had. Turning their cannons skyward, they blasted away with tremendous force.
⁶⁶
Though the sound was deafening and the fury impressive, it was a waste of ammunition. The nimble attack bombers could easily evade cannon fire.

Inouye felt as if every antiaircraft weapon, machine gun, and sidearm was being used to repel the attack, but from Takahashi’s position atop Yashiro Island, the air base seemed unable to defend itself.
⁶⁷
Takahashi had been in Kure that morning. When he heard
that carrier-based aircraft were heading their way, he jumped in his
Seiran
and flew it to the island for safety.
⁶⁸

Takahashi watched awestruck as enemy planes turned aircraft hangars into sieves. It was dispiriting.
⁶⁹
The real battle wasn’t taking place on the airfield though—it was happening in port. U.S. naval intelligence may not have known about the
I-400
’s mission, but it was hard to miss three gigantic submarines anchored in the harbor.

As wave after wave of enemy planes descended, Nambu hurried to get the
I-401
under way.
⁷⁰
Meanwhile, huge water geysers erupted nearby as the sub pulled away from the pier. Yata had no doubt they’d been spotted and were now the focus of attack.
⁷¹
Though the sub’s triple-mount batteries chased the enemy across the sky, it was pointless to remain. The
I-401
had put up a good fight, but she was being raked by machine-gun fire, and enemy bombs were closing in. The
I-400
might have been stuck in dry dock, but the
I-13
had already escaped. Nambu had to follow.

The
I-401
was fueled, so all Nambu had to do was find deep water and submerge.
⁷²
But as the sub backed away from the dock, an enemy plane released a bomb overhead. Inouye watched it tumble toward the sub as if in slow motion. He could feel in his bones it was going to hit them.
⁷³
But instead of striking the
I-401
, the bomb landed on the pier next to them.
⁷⁴
The explosion was only 100 feet away,
⁷⁵
so Inouye was close enough to see a gunner on the
I-400
get his face blown off. It only took a second, but the image burned into his brain forever.
⁷⁶
Captain Kusaka was also injured, hit by shrapnel in the head and thigh,
⁷⁷
as was the
I-400
’s chief navigator. By the time the explosion dissipated, at least six men were dead, two of them
Sen-toku
crew members.

So much smoke blanketed Kure that Nambu used it as cover.
⁷⁸
It was still a shock though when he passed the
Oyodo
. Rolled onto her side, her decks awash, the cruiser’s guns were blazing into the sky. Her fighting spirit made Nambu proud.
⁷⁹
Nevertheless, as soon as the
I-401
cleared the harbor, he submerged to periscope depth and waited out the rest of the attack underwater.