Key point: The fast kamikaze plane could kill, but it was too little, too late.
It is a fallacy that Germany was the only nation to develop combat jets in World War II. In truth, while Germany had the most advanced technology, all of the major powers had jet aircraft projects during World War II, including the United States, Britain, Russia, Italy and Japan.
The most well-known Japanese jet—and the only one that saw combat—was the Okha, a rocket-propelled and human-piloted kamikaze. But another Japanese jet actually flew before the war ended, and would have seen combat had it continued: the Nakajima Kikka.
Japanese scientists had actually studied jet engines as far back as the 1930s, despite little government support, and even a turbojet prototype by 1943. Tokyo also knew of German research due to Japanese observers who witnessed early tests of the legendary German Me-262 jet fighter in 1942, But it wasn't until the summer of 1944, when U.S. B-29 bombers began to pound Japan, that the Japanese Navy asked for the Kokoku Heiki No. 2, or Kikka ("orange blossom").
That the Kikka resembled an Me-262 is no coincidence—nor was it a matter of simple imitation. Japan's jet program was heavily derived from German research, but the aid was hardly straightforward. In July 1944, Luftwaffe chief Hermann Goering ordered that Japan be provided with blueprints for the Me-262, the Junkers Jumo 004 and BMW 003 turbojet engines, and even an actual Me-262 aircraft.
Yet the Japanese submarine carrying the plans from Germany to Japan was sunk by U.S. forces, though not before a Japanese envoy got off at Singapore with just a single cutaway drawing of the BMW 003 (arguably just as important as the blueprints for the Me-262, given that early jets were only as good as their unreliable engines). That was enough for Japanese engineers to build the Ne-20 turbojet, an engine that was superior to the homegrown Ne-12 that was originally supposed to power the Kikka.