Japanese Fighters in Defense of the Homeland, 1941–1944

Considering those words, the daring attack by the USAAF B-25B Mitchell bombers on April 18, 1942 must have come as a real shock to the Japanese high command. On that day 16 aircraft led by Lt Col James H. Doolittle launched from the USS Hornet and attacked targets in Tokyo, Yokohama, Nagoya and Kobe. The Japanese did not expect a raid by twin engine bombers and at such a long range from the Japanese islands. When the American force was first detected the time of the attack was estimated to be the morning of April 19 at the earliest, since the Japanese assumed it would be carried out by carrier-based aircraft with limited range. Therefore, when the B-25s appeared overhead they came as a complete surprise to the Japanese defenders. The air raid alarm was raised much too late and when the Army Ki-27 fighters were finally scrambled they either did not manage to intercept the intruders at all, or proved to be inadequately armed to inflict any serious damage. The U.S. bombers that were engaged and fired upon by the Japanese fighters emerged from the encounters virtually unscathed. The anti-aircraft artillery was equally ineffective: the low flying aircraft left the Japanese gunners precious little time to aim and fire their weapons.
From the military point of view the operation had very little impact, which quickly prompted the Japanese press to ridicule the strike as the “do-little raid”. However, for the Japanese high command the affair was no laughing matter. The fact that the enemy aircraft appeared in broad daylight over the Homeland, dropped their bombs on Tokyo and then safely flew on to China was a sober warning that had to be reckoned with. Following the spectacular failure of the country’s air defense, the issue would have to be addressed to avoid such embarrassments in the future.
For the Americans the Doolittle Raid was a major morale booster and a propaganda coup. It showed that an air strike against the Japanese islands was possible, despite the rather dire state of affairs in the Pacific. It also demonstrated that the only way to hurt the enemy on his own soil was through air attacks. However, launching more similar raids seemed impractical at that time: the potential losses would have very easily outweighed the necessarily meager gains of such operations. Americans needed a longer reach to bring war to the Japanese and they got it, just over a year later. It was called the Boeing B-29 Superfortress.


A formation of B-29s from the 58th BW photographed over China, en-route to Japan. The crews from the XX Bomber Command flew missions over Kyushu between June 15, 1944 and January 6, 1945


Organization of air defense

The work to create viable air defense structures began in Japan before the outbreak of hostilities in the Pacific. The task was delegated to the Imperial Japanese Army. July 12, 1941 saw the establishment of the Boei Soshireibu (General Defense Command) based in Tokyo, which was responsible for overall defense of the entire homeland area. Operationally, the Command was subordinate to the Rikugun Sanbo Honbu (Imperial Army General Staff), which was in turn directly subordinated to the Daihonei Rikugunbu (Imperial General HQ, Army Section). The new command’s tasking included coordination of defense of the Home Islands, as well as Formosa (Taiwan), Korea (Japanese: Chosen) and the islands of Ogasawara Shoto (Bonin), Nansei Shoto (Ryukyu), Kazan Retto (Volcano), Chishima Retto (Kurils) and Karafuto (southern Sachalin). The first commanding officer of the General Defense Command (Commander-in-Chief of Defense) was Taisho Otozo Yamada, who was replaced by Prince Taisho Naruhiko Higashikuni a day after the war in the Pacific had broken out (December 9, 1941). Higashikuni remained in command until the Boei Soshireibu was dissolved in April 1945.
The four main Japanese islands – Hokkaido, Honshu, Shikoku and Kyushu – were divided into four military districts (kanku) controlled by the Rikugunsho (Ministry of the Army). Hokubu-gun Kanku (Northern Military District) with its HQ in Sapporo was tasked with the defense of Hokkaido and the islands of Chishima and Karafuto. Tobu-gun Kanku (Eastern Military District) based in Tokyo covered the eastern part of Honshu (laying generally north of a line extending west from Suruga Bay to Wakasa Bay, passing north of Nagoya), including the Kanto region with the Empire’s capital. Chubu-gun Kanku (Central Military District) was headquartered in Osaka and tasked with the defense of central Honshu (laying west of the Eastern District and extending as far as a line drawn between Awaji Island and Shikoku, passing through Fukuyama north to Yonago), including the large industrial cities of Nagoya, Osaka and Kobe, as well as Kyoto – the nation’s historic capital. Seibu-gun Kanku (Western Military District) had its HQ in Fukuoka and was responsible for the defense of the western part of Honshu, as well as Shikoku and Kyushu.