Kamikaze and the Nakajima Ki 115 Tsurugi

Kamikaze, the Divine Wind, named in honour of the fortuitous typhoons that had wrecked Kublai Khan’s Mongol fleets in 1274 and 1281 and saved Japan from its first foreign invasions.

This small rocket powered aircraft was used by the Japanese navy at the end of WWII as a desperate means of attacking allied capital ships. 

After release from the mother aircraft (a Mitsubishi G4M2e "Betty" bomber) the rocket motor would ignite to give the vehicle a range of about 20 miles. 

The kamikazi pilot would then guide the plane, its nose laden with high explosive, onto the target.

The weapon had only limited success. Because American Navy fighters patrolled further than 20 miles away from any capital ship, the unwieldy mother ship/rocket plane combination proved a sitting duck for the American pilots.

  • Over 5,000 Kamikaze died in WW2

As the Japanese military became increasingly desperate to find ways of slowing the Allied advance, naval officer Ensign Mitsuo Ohta conceived a specialized suicide attack aircraft that would be inexpensive, easy to manufacture in large numbers, and equipped for high speed to avoid being shot down. 

Once the concept had been accepted, Yokosuka began developing the MXY7 Ohka (cherry blossom), a small, rocket-powered vehicle mounting a large warhead in the nose and intended to be carried to the target area by a Mitsubishi G4M2e "Betty" bomber. After being released, the Ohka would engage its rocket motors to make a high-speed dash to the target ship. Flight testing began in late 1944, but production of the Navy Suicide Attacker Ohka Model 11 began even before these tests were complete.

By March 1945, 755 of the Model 11 had been built, but initial deployments proved rather unsuccessful. Although difficult to shoot down because of its high speed, the Ohka was a sitting duck when still attached to the large, slow mother plane. In addition, the design proved to be very difficult to manoeuvre making it nearly impossible to hit even a slow moving target. In an attempt to improve the odds, a new version, the Model 22, began production. 

This model featured reduced wingspan and a smaller warhead allowing the Ohka to be carried by the much faster Yokosuka P1Y1 Ginga medium bomber. The Model 22 was also fitted with a Campini-type jet engine instead of rockets increasing the Ohka's range as well as reducing speed to allow better manoeuvrability. However, the jet engine was found to be vastly underpowered resulting in later versions powered by a turbojet, but none of these reached production before the end of the war. 

Japan also studied other methods for launching the Ohka, including a land based version and one carried by submarines. Although some 850 Ohkas were built, including trainer versions equipped with landing skids, only 50 ever saw combat sinking only three enemy ships.

There were two basic types of "special attack" groups. Kamikazes were line pilots who used their own aircraft, commonly fighters, to crash into enemy shipping. Thunder Gods were specially trained pilots who used the Ohka, the manned Japanese equivalent to the German V-1. Once the Ohka's vulnerability became apparent, some Thunder Gods switched to flying fighter-bombers overloaded with standard ordinance. The resulting unit was called the Kemmu Squadron, although it remained closely associated with the Ohka operations.

"One-third of the men on the ship were lost," retired U.S. Navy Rear Adm. Robert H. Spiro Jr. recalled of one attack. "So, it was personally devastating. It was heartrending. At the same end, for a few hours we saw blood. The ship was on fire. We thought the bow was going to break off."

The similarities don't end with the images and emotions. Looking back at Japan's infamous kamikaze, they seem more related to the pilots of al Qaeda than most Japanese today would like to admit.

They were fanatically devoted to their emperor, who was considered a god at the time. They were motivated by self-righteous anger against the West.

"Many Japanese do believe that they fought a just war," said Gregory Clark, president of Tama University in Japan. "[They believe] that they were fighting under extreme odds. And that anything was justified in the attempt to win this war, in which they were clearly the weaker power. And that included using kamikaze."

‘No Other Way to Fight Back’

More than 5,000 kamikaze died before the end of the war, and 20,000 were still awaiting missions. But a handful who did take off on suicide missions are still alive today.

"We had no other way to fight back," said Kenichiro Onuki, a volunteer who crash-landed before reaching his target. "This was the only way to prevent the U.S. military from advancing into our homeland." Another survivor, Kensuke Kunuki, said through a translator: "I had no fear. I wanted to sacrifice my life."

Kunuki suffered terrible burns when his plane was forced down by mechanical problems. He said his first thought at the time was that he wanted to try again because he hadn't killed any Americans.

‘They Were Not Fanatics’

In a new book on the kamikaze, Hideaki Kase, an outspoken Japanese nationalist, said there was no truth to the wartime propaganda that portrayed the kamikaze as a fanatical cult. He says they were no different than American youths who gave their lives in desperate military campaigns.

"They were not fanatics," Kase said. "They were not brainwashed. They were ordinary, young kids." Even today, he says, the West has difficulty grasping the notion that suicide is a noble act in some cultures. "Suicide can be honourable, positive, if that act was committed for the family or for the community or for the motherland," Kase said, adding that "patriotism — yes, patriotism" drove the kamikaze pilots.

Years Later, Heroic Depictions

Patriots? Immediately after the war, a demoralized Japan saw the kamikaze as symbols of military madness. The very word "kamikaze" became a synonym for crazy, reckless behaviour.

Yet few Japanese could ignore the fact that the kamikaze spirit was deeply ingrained in the Japanese psyche — duty, loyalty, sacrifice for the good of the group. Half a century later, the kamikaze are no longer viewed in such black-and-white terms.

Rare colour images of the suicide attacks from American archives are now included on popular videos in Japan. They are among a flood of retrospective books, documentaries and commercial films that portray the kamikaze more heroically.

Most of the kamikaze took off on their one-way missions from bases on Japan's southernmost island of Kyushu, and the largest base was in the town of Chiran.

Today, Chiran has become a testament to Japan's renewed fascination with the suicide pilots. It's now home to the country's largest kamikaze museum, which attracts nearly 1 million visitors a year. Many are moved to tears by the haunting faces of the boys about to die and the emotional poems and farewell letters they wrote.

"At the moment of death," a visitor remarked, "they must have been calling out for their mothers."

The museum has become a favourite of Japanese nationalists, who want Japan to stop apologizing for the war and to build a strong military again. For them, the kamikaze embodied Japan's samurai warrior spirit and should be idolized.

‘They Could Not Back Down’

That's exactly what Akihisa Torihama hopes will never happen. He is the grandson of Tore Torihama, a woman once called the kamikaze's "mama-san." She ran a small restaurant in Chiran where many of the pilots had their last meals and confided all the things they could not say in their heavily censored letters home.

"My grandmother told me the boys knew the war was lost, knew their lives were being thrown away by their commanders," he said through a translator. "They flew their missions because the social pressures on them were so great, they could not back down."

Today, he has transformed the old restaurant into an alternative kamikaze museum, to keep alive the message passed on by his grandmother — that the suicide pilots were not heroes, but the victims of fanaticism. And what's the verdict of the surviving kamikaze? Kuniki says he has no regrets. "My nation and my family were in danger," he said. "History will judge if we were right or wrong."

But Onuki said it was wrong to waste so many young lives. "Yes, we volunteered, but we were ordered to volunteer," he said. "It could have taken real courage to disobey that order."

‘Not a Single Civilian’

The surviving kamikaze, like most Japanese, bristle at suggestions that the kamikaze were the same as the al Qaeda suicide pilots. "They killed only military personnel," Kase said. "Not a single civilian." That distinction is not lost on Spiro, who as an American sailor who faced the kamikaze in combat. "At least it was a military tactic and they were not attacking our wives, children, friends, mothers," Spiro said.

Still, there's no question that recent events have cast Japan's suicide pilots and their motivations in a very new light. 

The Pacific war was a new kind of war. The scale was astounding and the distances involved immense. Both sides struck at their enemies thousands of miles from their home bases. Projection of power was the key concept here and in the American island-hoppng campaigns of 1943,44 and 45 it achieved a level both in concept and execution that can only be called epic. There were no titanic clashes of armies as experienced in Russia, France or even the Western Desert. Sea power was the instrument of victory and that sea power was centred on the aircraft-carriers that gave every task force its most potent weapon of either offence or defence. The carrier-borne planes swept the skies of enemy aerial resistance, the seas of enemy ships and allowed the fleet to take the soldiers and marines anywhere they wanted.

The ships couldn’t, however, take or hold a piece of land. The very idea of warships alone being able to cow recalcitrant natives into submission had died spectacularly with the failure of the Royal Navy at the Dardanelles and the Japanese were no ‘lesser race but a highly developed people with a potent war machine. When the fleets had done their job it was still up to the footsloggers to go ashore and and take the land. In the Pacific war this was a particularly bloody affair. 

All generals order their soldiers to fight until the last man and all armies expect their men to do this. Only the Japanese, in the modern era, have ever done this with any consistency. Folly, insanity, fanaticism one might say but no less a trial for the men trying to destroy such resistance. On atolls now remembered only by the men who fought on them the drama was played out a hundred times. Despite the pounding of naval guns and carrier planes, every yard had to be cleared with rifle, grenade and flamethrowers. Like most soldiers the Japanese knew that the deeper you burrow the better your chances, and they were veritable moles.

The most costly and terrible of these actions took place in 1945 on the island of Okinawa. To get their troops onto the beaches the US navy assembled a fleet of 1500 vessels. They carried over 550,000 soldiers, sailors, airmen and marines. They provide landing decks for hundreds of planes and they operated in hostile waters 6,000 miles from the continental United States. It was a floating city replete with repair shops, hospitals, kitchens, laundries, arsenals of millions of rounds of ammunition and tens of thousands of shells, living quarters, chapels, combat control centres, radar rooms and of course the teeth in the shape of massive guns and fast modern aircraft.

It took the Americans 83 days to secure the island and in that time the fleet stayed loyally offshore in the face of the fiercest attacks the US navy has ever had to suffer. The attackers were known as the Kamikaze, the Divine Wind, in honour of the fortuitous typhoons that had wrecked Kublai Khan’s Mongol fleets in 1274 and 1281 and saved Japan from its first foreign invasions. The official name was the Tokubetsu Kogeki Tai ,or Special Attack Group. The pilots were mostly young men, often very very young. They were given a rudimentary training and flew old antiquated planes that had no chance in any kind of air-to-air combat. 

There were, however, thousands of them and they possessed a singular determination. It’s not they wanted to die rather that they felt they had to die if their country was to have any prospect of survival. Once they had taken off there was no way they could return honourably and alone in their cockpits in the last moments of their lives they had only two possible finales; to die having failed or to die having succeeded. There is no young man who would choose the latter. They were almost always picked up on radar for , novice pilots that so many of them were, wave-hopping was a dangerous course. Combat air patrols flying the highly effective Hellcat fighter piloted by experienced naval aviators would strike them down in great numbers but still they came on. Some would penetrate the fighter screen and then would begin that intense battle between shipboard gunners who wanted to live and airmen who wished to die. 

The horror the sailors felt in the face of such suicidal rushes was compounded by the almost continuous nature of the attacks. One British correspondent noted that every Kamikaze seemed to be targeted exclusively on yourself. (The smaller British fleet near Formosa drew off only a few of the attackers from the main action at Okinawa and suffered much less than the Americans. One reason for this was the armoured decks of the British carriers.)

Militarily these attacks were foolishness on a grand scale and reflected the bankruptcy of the Japanese high command in the final days of the war. The results were paltry. Although eight carriers hit and some seriously damaged not one was sunk. The smaller ships of the radar pickets and anti-aircraft screens suffered badly and in total more than 300 kamikazes succeeded in crashing onto a ship. Only 30 of these ships were lost, another 288 damaged. To achieve this the Japanese squandered more than 3,500 planes. Vice-Admiral Takijiro Onishi, the man who had pushed hardest for Kamikaze attacks to be undertaken, committed seppuku (the ritual suicide in which cuts open ones own belly) when Japan surrendered. His whole strategy had been based on the impossibility of Japan ever giving up and in the 18 agonising hours it took him to die perhaps he felt remorse for the men he had needlessly sent to their deaths.

Nakajima Ki 115 Tsurugi

Good 3/4 front perspective view of a standard Ki-115a, probably taken shortly after the war.

The Japanese Army in early 1945 anticipated that the multitude of obsolescent combat aircraft and trainers it was collecting for suicide attacks (“taiatari”) would be insufficient to stop an invasion of the Home Islands. Accordingly, on January 20, 1945, the Army Air Staff instructed the Nakajima company to design and build a purpose-made suicide attack plane. It was to be easy to manufacture, maintain, and operate, and was to be capable of carrying a single bomb of up to 1,764 lbs. The undercarriage was to be jettisonable and reusable. It was to be powered by virtually any air-cooled radial engine with a power rating of from 800 to 1,200 horsepower. Specified maximum speed was to be 211 mph with the undercarriage in place, and 320 mph once it had been jettisoned.

Designated the Ki-115a Special Attacker Tsurugi (Sabre), the new aircraft was designed by Aori Kunihiro, with personnel of the Mitaka Research Institute and Ota Manufacturing Company assisting him in its design. It was intended to be built by semi-skilled labour, so the Tsurugi was quite simple – perhaps too simple. The fabric-covered tail surfaces had an inner structure of wood, the fuselage was of steel structure with a tin engine cowling and thin steel panels on the forward and centre sections, and the all-metal wings were of stressed-skin construction. A variety of surplus aero-engines could be used, fastened to the fuselage using four bolts, but the 105 examples actually built were all powered by the Nakajima [Ha-35] 23 (Ha-25) fourteen-cylinder radial, the Army version of the Navy’s Sakae engine. The pilot sat quite far back behind the engine, above the wing trailing edge. The sole armament, as stated above, was to be a single bomb of up to 1,764 lb., attached to a recessed crutch under the fuselage centre section. The undercarriage, as noted, was non-retractable, being jettisoned shortly after take-off for a suicide mission.

This shot from the rear quarter displays the sleek lines of the Ki-115, marred by the clunky-looking undercarriage.

Flight tests commenced as soon as the first prototype, manufactured by Mitaka, was ready in March 1945. And although the Tsurugi was easy to build, its actual performance during ground tests was quite poor. The undercarriage was unbelievably crude, lacking as it did shock absorbers, and the pilot’s field of vision for taxiing was maddeningly inadequate. In the air, the aircraft was hard even for an experienced test pilot to handle, so a great many modifications were required before turning green pilots loose with it. In June 1945, a redesigned undercarriage with proper shock absorbers was fitted and auxiliary flaps were attached to the wing trailing edges. Nevertheless, there were a number of fatal accidents involving the Ki-115 even after the modifications were made (indeed, one could say it caused the “premature suicide” of a number of its unfortunate would-be pilots!). Provision was made on all of the 104 production examples for two solid-fuel rockets under each wing to add boost to the Ki-115’s final dive, but none of these aircraft were ever used in combat.

The Japanese Navy expressed an interest in the Ki-115, and so two examples were delivered to the Showa Airplane Co. Ltd., makers of the L2D transport. They were to be used as prototypes for the Toka (Wisteria) Suicide Attacker, the Navy’s version of the Tsurugi, which was to be powered by various kinds of reconditioned surplus engines.

A Ki-115 shortly after the war, with its propeller removed to prevent unauthorized flight.

The Ki-115b was a projected variant with wooden wings of increased area fitted with proper flaps, and with the cockpit moved forward to improve the pilot’s vision. None were completed, however, and the Ki-230, a further development, was fated never to leave the drawing board due to the war’s end.

As a final word, it should be pointed out that, aside from the idea of suicide attacks itself (which Westerners would find disturbing), such a plane as the Ki-115 was tactically very limited. For example, what if a formation of Tsurugis was sent to attack an Allied fleet, and they couldn’t find it where reconnaissance reports had said it would be? Since they lacked landing gear, the Ki-115s would have to waste valuable time and fuel searching, perhaps in vain, for targets, and if they ran out of fuel, they’d have no choice but to land in the sea – and because Japan had virtually no air-sea rescue system, the pilots’ lives would be lost meaninglessly. And knowing that the Ki-115 lacked on-board guns, its pilots would be wholly dependent on the escort fighters to fight for them and force a way through Allied interceptors – and what if the interceptors overwhelmed the escorts? In the end, the Ki-115 must remain a footnote, an oddity, in combat aircraft design.

A line-up of propeller-less Ki-115s in a roofless hangar.

Nakajima Ki-115 Tsurugi Technical Data

Single-seat, single-engined suicide attack plane, of mixed construction as per the text.

Pilot in open cockpit.

One Nakajima [Ha-35] 23 fourteen-cylinder air-cooled radial engine, rated at 1,130 hp for take-off and 980 hp at 19,685 ft.

One 551-lb., 1,102-lb., or 1,764-lb. bomb, semi-recessed under the fuselage.

Dimensions, weights, and performance:
Wingspan, 28 ft. 2 9/16 in.;
length, 28 ft. 5/8 in.;
height, 10 ft. 9 15/16 in.;
wing area, 133.472 sq. ft.;
empty weight, 3,616 lb.;
loaded weight, 5,688 lb.;
maximum weight, 6,349 lb.;
wing loading, 42.6 lb./sq. ft.;
power loading, 5.1 lb./hp;
maximum speed, 342 mph at 9,185 ft.;
cruising speed, 186 mph;
climb, N/A;
service ceiling, N/A;
range, 745 miles.

(Ki-115b) (Note -- all performance figures for this variant are design estimates)
Wingspan, 31 ft. 10 11/16 in.;
length, 28 ft. 5/8 in.;
height, 10 ft. 9 15/16 in.;
wing area, 156.076 sq. ft.;
empty weight, 3,726 lb.;
loaded weight, 5,798 lb.;
maximum weight, N/A;
wing loading, 37.1 lb./sq. ft.;
power loading, 5.1 lb./hp;
maximum speed, 385 mph at 19,030 ft.;
cruising speed, N/A;
climb, N/A;
service ceiling, 21,325 ft.;
range, 745 miles.

A rather tired-looking Ki-115 Tsurugi sits forlornly beside an airstrip just after war's end.