The aircraft was 6.07 metres long. It carried a 1,200-kilogram warhead in its nose. The cockpit had a basic compass, an airspeed indicator, and a single switch that started three solid-fuel rocket motors. There was no landing gear. There was no parachute. The pilot, on enlistment, signed a formal agreement that he would not return.

The Yokosuka MXY-7 Ohka — Japanese for “cherry blossom” — was the first purpose-built suicide aircraft in history. The Allies, who fought it from March 1945 until the end of the war, called it Baka. The word translates as “fool.”

A Weapon Born of Desperation

By autumn 1944 Japan was losing on every front. The American B-29 raids were accelerating. Allied submarine warfare had cut off Japanese oil supplies. Conventional kamikaze pilots — fighters loaded with explosives and flown directly into Allied warships — were achieving real results, but the aircraft were obsolete and slow. American carrier-based combat air patrols were shooting them down before they reached their targets.

The Imperial Japanese Navy’s Aeronautical Research Institute, the Kugisho, proposed a different approach: build an aircraft optimised purely for the suicide mission. Cheap. Fast. Hard to intercept. Carried to the target by a conventional bomber. The pilot would only have to fly the last few minutes — the part where speed and inevitability mattered most.

How It Worked

An Ohka mission began with a Mitsubishi G4M “Betty” twin-engine bomber, modified with an Ohka clamped under the bomb bay. The Betty climbed to 8,000 metres and approached the target fleet at 320 km/h. At roughly 30 to 35 kilometres from the target, the Ohka pilot — already strapped in his cramped cockpit, who had ridden along since takeoff — was released.

The Ohka glided downward, building speed. Once aligned with the target, the pilot ignited the rocket motors. The little aircraft accelerated to 650 km/h horizontally, then transitioned into a terminal dive that hit nearly 1,040 km/h — Mach 0.85, faster than any Allied fighter could catch. The single switch in the cockpit triggered the warhead on impact.

One Ohka strike on the destroyer USS Mannert L. Abele on 12 April 1945 killed 84 men and broke the ship in half. It was the first warship in history sunk by a guided weapon — fifty years before “guided weapon” became a normal phrase.

The Allied Counter

The American counter-strategy was simple: kill the bombers before they could release. The Ohka had no usable range without its mothership. The G4M Betty, weighed down by an Ohka, was 50 km/h slower than normal and could not manoeuvre. American F6F Hellcats and F4U Corsairs were given strict instructions to focus fire on Bettys carrying Ohkas, and to ignore unloaded escort fighters until the Ohka was destroyed.

The strategy worked. Of 155 Ohka combat sorties, only seven scored direct hits on Allied warships, and three of those were on already-damaged ships. The vast majority were destroyed in their motherships before release.

The Pilots

The Ohka programme drew its pilots from the same pool as the conventional kamikaze units. Most were university students conscripted in 1944. Their training was minimal — the aircraft was, after all, designed for one flight only. Many never got to make even that flight; their motherships were shot down before release, killing the Ohka pilot along with the bomber crew.

Three Ohkas survive in museums today. Each is small, neat, painted in green-grey camouflage, and unsettlingly cheerful in appearance — a reminder that the most cruel weapons in aviation history are not always the largest.

Sources: Imperial War Museum, National Air and Space Museum, “Suicide Squads” by Richard O’Neill.