Operation Storm: Japan's Top Secret Submarines and Its Plan to Change the Course of World War II (25 page)

It was important to maintain crew morale in the face of such a delay. To this end, Nambu commissioned a ship’s song. Usually, individual vessels didn’t have an anthem. The
I-401
was an unusual case.
²
Nambu asked his crew for lyrics. Then, after editing their contributions, he had the Sasebo Naval Band set them to music. When it came time to rehearse, his crew lustily sang their flagship’s new song.

Symbolic rituals required a surprising amount of Nambu’s attention. They were necessary though to preserve IJN tradition. For example, every IJN ship had an onboard shrine where the crew prayed for success. The
I-401
’s primary shrine was in the control room. But a statue of Ise, the spirit who watched over submariners, was needed to fill the niche. Fortunately, the Grand Shrine at Ise, one of Japan’s most sacred Shinto sites, was nearby. Nambu also needed a written fortune for the sub, to reassure the crew about their future. Too busy to get it, he sent his chief navigator to fetch one instead.
³
Sometimes superstition was more comforting, especially when logic suggested something less satisfying.

The Imperial Japanese Navy officially organized the
Sen-toku
subs into SubRon 1 on December 15, 1944.
⁴
The next day the
I-13
was completed.
⁵
Captained by Cdr. Katsuo Ohashi, the
I-13
immediately departed for her shakedown cruise in the waters off Kobe.
⁶

Ohashi was the third
Sen-toku
captain to have served in the Indian Ocean. It’s not clear whether he knew Ariizumi personally. Still, he’d sunk a fair number of Allied merchant ships as skipper of the
I-56
(later the
I-156
). Interestingly, when he came across Australian airmen in a lifeboat in 1942, he declined to massacre them despite his officers’ entreaties.

“The war situation won’t be affected,” Ohashi told them. “Let’s not partake in any senseless killing.”
⁷

Fourteen days after the
I-13
was commissioned, the
I-400
was also handed over. It was just two days before the New Year,
⁸
and the
I-401
still wasn’t ready. Nambu could only wait enviously as his sister subs headed out to sea.
⁹

A
T THE SAME
time SubRon 1 was being organized, the 631st
Kokutai
, or air group, was formed with Ariizumi in command. Ten
Seiran
bombers, three for each of the two
I-400
subs and two for the
I-13
and
I-14
, respectively, would form the heart of the unit, with additional
Seiran
for training and replacement. It was a much-reduced force compared with Admiral Yamamoto’s original vision. Yamamoto’s plan had called for 18 subs and 44
Seiran
before the underwater aircraft carriers had been reduced in number. By June 1944 Aichi had completed a measly four
Seiran
, with a production capacity limited to one per month.
¹⁰
This meant that only ten
Seiran
would be ready by the end of the year, far short of the modified goal.
¹¹
And two of these weren’t even combat aircraft, they were trainers. As a result, when the
Sen-toku
subs began launching in December, not one
Seiran
was ready for assignment. They were still undergoing flight testing.
¹²

Engine problems were partly responsible for the slow pace of
Seiran
production.
¹³
You couldn’t do anything without a reliable engine, which led to a cascading series of consequences. Shortage of aircraft meant flight tests were delayed, which in turn meant fewer planes were available for pilots to qualify in. Additionally, more and more pilots were being transferred to Yokosuka in anticipation
of the 631st being formed. When new pilots arrived, they had to make do with alternative floatplanes like Aichi’s
Zuiun
, which they disparagingly referred to as a “toy.”
¹⁴
Frustrations mounted.

The situation was further complicated by the surface fleet, which got first dibs on experienced pilots.
¹⁵
There were so few aviators with combat experience this late in the war that many of the 631st’s pilots were green. Almost none of the new arrivals had the dive-bomb experience necessary to attack the Panama Canal.
¹⁶
Though specialized training could make up for the shortfall, they had to have planes to train in, and that continued to be an issue throughout the winter months.

Ens. Kazuo Takahashi was one of the first pilots to show up for
Seiran
instruction. Confident and handsome, Takahashi had been a seaplane instructor when the war started and later became a floatplane pilot aboard the
1–37
.
¹⁷
It probably wasn’t a coincidence that he’d been assigned to the 631st, since he’d known Ariizumi when they’d served together in SubRon 8.

Takahashi had never even seen the ocean before enrolling in the navy’s Junior Pilot Training Course,
¹⁸
yet by the time he arrived at Yokosuka Naval Air Station, he was a veteran pilot. His seaplane experience made him an ideal choice for a
Seiran
pilot. When Takahashi arrived at Yokosuka on August 24, 1944, he was given a
Seiran
instruction manual and told to read it. A week later he donned his flying helmet lined with rabbit fur and flew his first
Storm from a Clear Sky
.
¹⁹

Takahashi began flying
Seiran
in September. He measured takeoff, landing, ascent, and cruising speeds, as well as fuel consumption and descent rates. There was also some formation flying. What Takahashi liked best though was testing the
Seiran
’s responsiveness. The plane handled so well, he soon fell in love.
²⁰

By mid-September, Takahashi was flying the
Nanzan
, or land version of the
Seiran
. He found the plane lighter and faster than the sea-based version.
²¹
He especially enjoyed its acrobatic abilities, finding it handled as well as a Zero fighter,
²²
high praise considering the plane was merely an attack bomber.

Come October, Takahashi was ready to begin torpedo training.
After learning how to operate the bombsight, he took to the air over the Otake target range carrying a torpedo. Dropping to an altitude of only 100 feet, he skimmed across the ocean at breakneck speed. Centering the target in his bombsight, he pressed the drop activation switch just below the grip on his control stick. When the torpedo fell, a miniature light verified its release.
²³
Takahashi already knew that it had dropped though—because his plane leaped 60 feet into the sky.
²⁴

Takahashi watched with anticipation as his torpedo raced toward the target. After 300 feet it inexplicably slowed, veered to the left, and began emitting smoke. He was crestfallen—he’d expected it to explode. He didn’t realize it was a dummy.
²⁵
Takahashi had one more chance to practice dive-bombing that month, but he would need a lot more training before he became an expert.

By November 15 engine production had improved enough that Takahashi was sent to collect another
Seiran
from Aichi’s factory.
²⁶
Aichi’s skunkworks were in a stand-alone building separate from its main plant.
²⁷
Seiran
were built in a large steel-framed hangar with a curved roof, floor-to-ceiling windows, and metal support columns that looked like bridge trusses. Built one at a time, it was a customized approach compared to the assembly lines favored by the United States. It was the best Aichi could do given the specialized nature of the aircraft.

When Takahashi arrived, Aichi’s assembly facility had a poster on the wall reading, “Let’s pull together!”
²⁸
High school students were building much of the plane by hand. The Ministry of Education had suspended classes so students could work in war production.
²⁹
Many of the workers were girls 12 to 15 years old,
³⁰
which resulted in some unexpected consequences. One
Seiran
fuselage was found to have a drawing of a Japanese woman scratched in its surface—not exactly regulation markings for a combat aircraft. The system worked though and to prove it, two new
Seiran
stood ready for Takahashi to fly.

L
T
. A
TSUSHI
A
SAMURA
arrived at the Yokosuka seaplane base in November 1944. Twenty-two years old and small for a pilot,
³¹
he had no trouble fitting into a cockpit. He was already a seasoned flyer—his specialty was twin-seater seaplanes. Like Ariizumi, he was an Etajima graduate,
³²
but he was more senior and had taught at Kashima Naval Air Station. Most recently he’d been an aircraft officer aboard the cruiser
Aoba
.
³³
When the
Aoba
was severely damaged during the Battle of Leyte, Asamura was transferred to Yokosuka. There were never enough experienced seaplane pilots to go around.

Asamura was on the tarmac when he noticed a bright orange aircraft buzzing in the sky overhead.
³⁴
The color designated an experimental plane, which naturally piqued his curiosity.

“What’s that?” Asamura asked Lt. Cdr. Tadashi Funada, the
Seiran
’s first test pilot.

“It’s the most secret of secret planes. It’s called
Seiran
, and we only have two so far. Once we’ve manufactured thirteen, we’ll load them onto submarines and bomb the Panama Canal. You’re going to be the flight leader.”
³⁵

Asamura’s chest swelled with pride. Finally, the bantam pilot was getting a mission commensurate with his desire.

Asamura may have been a talented pilot, but he was a difficult personality. A stickler for protocol, he angered easily when someone crossed his imagined boundaries. This keen sense of “correctness” meant he followed orders with exceptional dedication. It also meant he was rigid and unyielding. Whereas Takahashi was arrogant and critical, Asamura could be petty and vindictive. Their differing personalities would eventually clash. In the meantime, they focused on flying.

Seiran
flight-testing was far enough along that by November 24, the plane was officially accepted by the IJN.
³⁶
Aircraft production was dealt a blow, however, when a December 7 earthquake shook Nagoya. The quake lasted five minutes, killed 1,000 people, and caused heavy damage. Though no
Seiran
were destroyed, their wing jigs were twisted like taffy, even though some metal pipes
were 12 inches thick.
³⁷
Sen-toku
personnel were rushed to the plant to assist in the cleanup.
³⁸
Meanwhile, production was brought to a standstill.

When the 631st was officially formed eight days later, no
Seiran
were available for the unit.
^*
39
They were still being tested. Asamura may have been proud to be assigned to the air group, but Takahashi wanted out of sub-borne airplanes. One reason was that he wouldn’t be flying in the relative safety of the Indian Ocean but deep in the heart of enemy territory. While Asamura was grateful to die for his country, Takahashi took a more jaded view. Since he considered defeat inevitable, little would be gained by his death in battle. In other words, being assigned to the 631st was “the worst possible news.”
⁴⁰

F
INALLY, ON
J
ANUARY
8, 1945, the
I-401
was commissioned under the cloudy skies of Sasebo. Since the sub was top secret, few people attended the ceremony. When it was over, Nambu sailed the
I-401
quietly out of the harbor.
⁴¹

Although 60 percent of the
I-400
’s crew had limited experience aboard a sub,
⁴²
Nambu felt he had few greenhorns among his men.
⁴³
Forty percent of experienced submariners is low for a combat boat. It was certainly fewer than a U.S. sub was comfortable carrying.

Nambu didn’t linger in the waters off Kyushu.
⁴⁴
So many U.S. submarines were in the area that there was a saying: You could walk across their periscopes from Singapore to Japan without getting your feet wet.
⁴⁵
Nambu was right to be concerned. U.S. subs considered the sea lanes around Kyushu to be prime hunting ground, and the
I-401
made a tempting target.
⁴⁶

Nambu quickly headed for the safe waters of the Inland Sea with Ariizumi onboard. They met up with the
I-400
and
I-13
near
Kure, where they conducted dive and surface drills, practiced trimming the boat, and did underwater navigation exercises.
⁴⁷
After repeated practice, the
I-401
could crash-dive to periscope depth in just under a minute—a significant achievement given the size of the boat but almost twice as long as the
Segundo
required.