In the later stages of the Second World War in the Pacific, Japan was desperate. They turned to a new tactic - kamikaze. Although suicide attacks had been used haphazardly before, the kamikaze campaign trained attack squadrons specifically for this purpose, and brought into combat a new aircraft - the Yokosuka MXY-7 Ohka - the only jet-powered suicide aircraft.
They first saw action at the Battle of Okinawa in 1945, where extensive damage was done to the Allied fleet. But overall, how effective were these aircraft and this campaign?
Why Japan's kamikaze campaign ultimately failed
Voice over: "In late 1944, the Allied forces were advancing towards the Japanese home islands. While Germany was months away from surrender, in the Pacific Theatre, American troops were closing in on Japan, taking the islands one by one.
The Japanese had lost several major battles, hundreds of men and aircraft, and they were struggling to compete with the Allied industrial capacity. And yet despite their heavy losses, they were unwilling to surrender. A radical strategy emerges, Kamikaze."
Ian Kikuchi: "In the later stages of the Second World War in the Pacific, Japan was faced by overwhelming American naval power. Increasingly unable to make effective air attacks against American ships, Japanese forces turned to suicide attacks, using pilots flying aircraft laden with bombs as improvised missiles, in the hope of destroying Allied ships at the cost of the aircraft and the pilot’s life. The suicide attackers were known as the kamikaze.
Their name comes from two Japanese words, ‘kami’, meaning god, or divinity, and ‘kaze’ meaning wind or air, and so kamikaze is usually translated as ‘divine wind’."
Voice over: "In 1944, a Special Attack Force was formed, a group of official kamikaze pilots. Their first significant action took place at the Battle of Leyte Gulf in October 1944."
Ian Kikuchi: "At Leyte Gulf, the Japanese attempted to prevent Allied forces from occupying the Philippines, precipitating one of the largest naval battles in history."
Voice over: "During the battle, five kamikaze A6M Zeros attacked several escort carriers. All five missed their targets or were destroyed by anti-aircraft fire. However, as one aircraft aborted, they aimed instead for USS St Lo, diving into the flight deck and sinking the carrier. It was the first major warship sunk by a kamikaze attack. The following day, dozens more kamikaze strikes were made. In total, five ships were sunk and 23 were heavily damaged by kamikaze attacks. After the Battle of Leyte Gulf, the Japanese decided to expand their kamikaze strategy."
Ian Kikuchi: "Most of the aircraft used for kamikaze strikes are standard Japanese combat aircraft. Foremost among them is the Mitsubishi Zero fighter. This aircraft had given the Japanese navy control of the skies through 1941 and 1942, but by the start of the kamikaze campaign in 1944, the Zero is outclassed by more powerful American fighters.
This particular aircraft behind me was operated in the Pacific and was abandoned on the island of Taroa when it became unmaintainable. Had it still been serviceable, maybe it might have been used as a kamikaze in 1944 or 1945. It was recovered, as a wreck, in the 1990s and later passed into the Imperial War Museum’s collection. During the kamikaze campaign, around 650 Zero fighters are expended, more than any other type, but the campaign sees the use of a wide variety of aircraft, even including wooden biplane trainer planes."
Voice over: "Alongside the use of Zeros and other aircraft in the Kamikaze campaign, the Japanese also began to develop an aircraft specifically designed for suicide missions – the Yokosuka MXY-7 Ohka."
Ian Kikuchi: "Work begins on the design of the Ohka in 1943, actually before the first kamikaze attacks are made. The idea comes from a Japanese transport pilot named Mitsuo Ōta. Initially his designs go nowhere, but in 1944 he’s summoned to present his design to the Japanese Navy. From June 1944, following heavy Japanese aircraft losses in battle around the Mariana Islands, development transfers to the Japanese naval arsenal at Yokosuka. Test flights begin in October 1944, with a successful test flight of a rocket-powered Ohka in November 1944."
Voice over: "The IWM’s Ohka is a model 11 – the only operational variant."
Ian Kikuchi: "The Ohka is rocket-powered glider carrying a large, 1,200-kilo explosive warhead. It’s about 6 metres long and 5 metres wide. With its rockets lit it could reach 400mph, and in its final dive its speed might reach as much as 575mph.
The Ohka’s rockets had limited range, and so it had to be carried into action by a larger aircraft, typically a twin-engine Mitsubishi G4M bomber. Once the bomber reached the target area, the Ohka pilot would detach himself from the bomber, ignite his rockets, and aim for an enemy vessel."
Voice over: "Once the rockets were ignited, the pilot would fly the missile towards the target. The Ohka could reach incredible speeds, making it difficult to counter the attack, but also difficult for the Ohka pilot to control. Updated versions of the Ohka were in development aiming to fix some of the aircraft’s flaws, but these were not developed in time, and only the Ohka-11 saw active service.
The Allied troops who encountered these attacks referred to the aircraft as Baka Bombs, a Japanese word meaning foolish. The idea of a suicide aircraft was an alien concept in the west. But for the Japanese, their culture had long understood suicide as something that, under certain conditions, was honourable and appropriate behaviour. The kamikaze didn’t necessarily think of their mission as one of suicide. Instead, they saw it as fulfilment of their duty to their Emperor, a ruler widely believed to be divine. The word Ohka in Japanese means Cherry Blossom."
Ian Kikuchi: "The cherry blossom is a popular symbol in Japanese culture. Cherry blossom is beautiful, but its beauty is short-lived, and soon the petals fall from the trees, or are blown away by the wind. For the Japanese, the cherry blossom has become a symbol for the fleeting nature of human life."
Collections footage voice over:
"What did you think of the kamikaze? The whole tactic…?"
Douglas Bates: "Bloody idiots. For the hundreds they sent out, there were only a few that succeeded. Certainly did a hell of a lot of damage, which you didn’t have much defence against. But the majority of them just crashed into the sea and that was it. They didn’t get shot down, or they ran out of petrol, or they missed their targets. Because they weren’t very well trained. They were only taught to fly a plane from here to there and that’s all they knew. And we had so many guns on the ship. Incredible. Not only 4mm or 5mm, but Oerlikon, pompoms and all sorts of things. But if you’ve got that kamikaze determined to get through, that’s it, nothing’s going to stop him, doesn’t matter how much aircraft fire you’ve got."
Voice over: "The Japanese ramped up their kamikaze campaign, but the Allied naval forces had learnt lessons during the battle of Leyte Gulf and had begun to prepare for the threat of kamikaze."
Ian Kikuchi: "The Allies had a number of defences against the kamikaze. Away from the ships themselves, the key defence was combat air patrol by naval aircraft, trying to intercept incoming Japanese aircraft before they reached Allied ships. Naval aircraft were also used to attempt to suppress Japanese airfields, attacking kamikaze as they took off, bombing runways, and attacking aircraft on the ground.
The Allies also used destroyers as radar pickets; these were small warships fitted with radar. Positioned twenty miles out from the main fleet, these ships provided early warning of incoming air raids. Unfortunately for their crews, these ships were very exposed, and were often subjected to attacks by multiple kamikaze.
Aboard ship, the key defence was provided by anti-aircraft guns. A large fleet aircraft carrier like the USS Bunker Hill would carry a dozen 5-inch anti-aircraft guns, as well as dozens of smaller 40mm and 20mm guns. New technology, such as proximity fuses and radar gun-laying, made anti-aircraft fire more effective.
Finally, there was damage control. By 1944 the Allied navies had sophisticated and well-trained damage control procedures. It was rare for a kamikaze strike to sink a vessel outright, and so a critical factor in a vessel’s survival was the efficiency with which a ship’s crew could extinguish fires, repair structural damage, and restore a ship’s systems."
Voice over: "In October 1944, a special attack Squadron was formed specifically to fly the Ohka into battle, the Japanese 721st Naval Air Squadron, known as the Jinrai Butai, which translates as Divine Thunderbolt Corps, or the Thunder Gods."
Ian Kikuchi: "I think inevitably different pilots had different feelings. Kamikaze pilots are typically thought of as being fanatical zealots, eager to die for their country and their Emperor. It’s likely that some really did feel that way. Others will have had more mixed feelings, and acted more out of a sense of obligation than enthusiasm. And not all kamikaze pilots were volunteers; after the volunteers ran out others were shamed or coerced into ‘volunteering’."
Voice over: "By late 1944, soon after the first successful test flight of the Ohka, the US forces were in reach of the home islands. By the spring of 1945, the Japanese strategic situation was dire. In summer 1944 US forces captured the Marshall and Palau islands. By November, islands like Tinian, Saipan and Guam, were bases for US heavy bombers able to strike at the Japanese home islands. This leads to devastating air raids, including against Tokyo in March, which may have killed 100,000 people."
Ian Kikuchi: "At sea, US submarines were sinking Japanese merchant shipping, hampering the import of vital raw materials. On land, Japanese manpower is being consumed in battles in China, in Burma, as well as in New Guinea and the south Pacific. For the Japanese, Okinawa isn’t just another Pacific island, it’s actually part of Japan proper, so the looming battle of Okinawa has political and psychological significance as well."
Voice over: "The initial invasion of Okinawa took place on 1 April 1945 - the largest amphibious assault in the Pacific Theatre. It becomes the bloodiest of the battles in the Pacific, particularly for the Japanese."
Ian Kikuchi: "For the invasion of Okinawa, the Allies assemble a massive invasion fleet. Dozens of aircraft carriers, 18 battleships, two dozen cruisers and well over a hundred destroyers and destroyer escorts. The Allied invasion fleet has enormous firepower, in both naval guns and aircraft. At first, American troops make rapid progress, because the Japanese choose not to resist the initial landings. Instead, the Japanese build immensely strong defensive positions, particularly in Okinawa’s mountainsides. These defences prove enormously costly to overcome. In addition, tens of thousands of Okinawan civilians are killed, having suffered terribly."
Voice over: "At the Battle of Okinawa, Kamikaze became a core part of the Japanese naval defence strategy. And it was here that the Ohka were brought into combat. Around 850 Ohka were built in total, but relatively few saw combat. In March 1945, the Ohka flew their first combat sortie, but it had resulted in failure."
Ian Kikuchi: "One of Ohka’s biggest weaknesses was its limited range, and its need to be carried into battle by a larger bomber plane. Its parent aircraft was vulnerable to interception. In their first combat sortie, the Japanese attacked with 16 bombers carrying Ohka, escorted by 30 Zero fighters. They were intercepted by two squadrons of US naval fighters, with the loss of every single bomber and their Ohka."
Voice over: "On the 1 April 1945, the first day of the invasion of Okinawa, six G4Ms carried Ohkas into battle. It’s uncertain whether any of the Ohkas hit their targets, but the USS West Virginia was damaged. None of the G4Ms returned. Just over a week later, nine G4Ms and Ohkas went into battle again. This time, a destroyer was hit and sunk – the USS Mannert L. Abele. Over April, May and June, numerous attacks were launched by the Ohkas and the G4MS against the US fleet off Okinawa. Many of the G4Ms were destroyed, and many Ohkas failed to hit their targets, likely falling victim to anti-aircraft fire.
Alongside the Ohka, the Japanese continued to fly Kamikaze missions with Zero fighters and a variety of other aircraft and even suicide boats. Between April and June the Japanese flew over 400 kamikaze sorties at Okinawa. The British Pacific Fleet also came under fire from kamikaze attacks in the battle. Significant damage was done to the Task Force, but nothing debilitating. The armoured flight decks of the British carriers meant they faired better under these bombardments than the US carriers with flight decks made of wood. Ultimately, Kamikaze missions played a significant role in the Battle of Okinawa, but it was not enough to turn the tide for the Japanese."
Ian Kikuchi: "Around 350 vessels were hit by kamikaze. 47 were sunk and the rest were damaged. Of the ships sunk, none were strategically important, and all could be replaced. Among the damaged ships were thirty-one aircraft carriers of different types. In some cases, for instance to USS Bunker Hill, the damage was severe enough to put the ship out of action for months. But the kamikaze could never inflict enough damage to derail Allied naval operations.
Nonetheless, their human toll was appalling. The Japanese expended 2600 aircraft in kamikaze attacks, and with them the lives of 4000 airmen. The attacks killed more than 7000 Allied naval personnel, and wounded many more. the kamikaze failed for a variety of reasons. I think a big one is faulty assumptions.
The Japanese overestimated how many kamikaze would be able to evade Allied fighters and anti-aircraft guns. They overestimated the likelihood of direct hits against enemy ships, and overestimated how much damage a crashing aircraft could do to a large warship. The Japanese also overestimated how much impact the kamikaze would have on Allied strategic decision-making; they thought the psychological effect of their attacks would be so demoralising that it would reduce the Americans’ will to fight the war to the bitter end. They were wrong."