Early in the Pacific Campaign of World War II he was the head of the Naval Aviation Development Division in the Ministry of Munitions and was responsible for some of the technical details of the attack on Pearl Harbor in 1941, under command of Admiral Isoroku Yamamoto. Ōnishi himself opposed the attack on the grounds that it would lead to a full-scale war with a foe that had the resources to overpower Japan into an unconditional surrender. Nevertheless, his 11th Air Fleet had a critical role in the operations, attacking American forces in the Philippines from bases in Taiwan. On 1 May 1943, he was promoted to vice admiral. As an admiral, Ōnishi was also very interested in psychology, particularly as related to soldier′s reactions under critical circumstances; in 1938 he published a book on this subject: War Ethics of the Imperial Navy. After October 1944, Ōnishi became the commander of the 1st Air Fleet in the northern Philippines. While he is commonly credited with having devised the tactic of suicide air attacks on Allied aircraft carriers, the project predated his tenure and was one that he originally opposed as "heresy". Following the loss of the Mariana Islands, and facing orders to destroy the U.S. Navy′s aircraft carrier fleet in advance of "Operation Sho", Onishi changed his position and ordered the attacks. In a meeting at Mabalacat Airfield near Manila on 19 October 1944, Ōnishi, who was visiting the 201st Navy Flying Corps headquarters, said: "In my opinion, there is only one way of assuring that our meager strength will be effective to a maximum degree. That is to organize suicide attack units composed of A6M Zero fighters armed with 250-kilogram bombs, with each plane to crash-dive into an enemy carrier... What do you think?" He addressed the first kamikaze unit, and announced that their nobility of spirit would keep the homeland from ruin even in defeat. After his recall to Tokyo, Ōnishi became Vice Chief of the Imperial Japanese Navy General Staff on 19 May 1945. Just before the end of the war, Ōnishi pushed for continuing the fight, saying the sacrifice of 20 million more Japanese lives would make Japan victorious.
Death
Ōnishi committed ritual suicide in his quarters on 16 August 1945, following the unconditional surrender of Japan at the end of World War II. His suicide note apologized to the approximately 4,000 pilots whom he had sent to their deaths, and urged all young civilians who had survived the war to work towards rebuilding Japan and peace among nations. He also stated that he would offer his death as a penance to the kamikaze pilots and their families. Accordingly, he did not use a kaishakunin, and died of self-inflicted injuries over a period of 15 hours. The sword with which Ōnishi committed suicide is kept at the Yūshūkan Museum in Yasukuni Shrine in Tokyo. Ōnishi′s ashes were divided between two graves – one at the Zen temple of Sōji-ji in Tsurumi, Yokohama, and the other at the public cemetery in former Ashida village in Hyōgo prefecture.
On film
Japanese actor Tōru Abe portrayed Ōnishi in the 1970 film Tora! Tora! Tora!.
Takijirō Ōnishi was also portrayed in the Toei 1970 production Saigo no Tokkōtai, The Last Kamikaze in English.
Toei produced a biographical film in 1974 called Ā Kessen Kōkūtai, Father of the Kamikaze in English.
Books
Peattie, Mark R., Sunburst: The Rise of Japanese Naval Air Power 1909-1941, Annapolis, Maryland: Naval Institute Press, 2001,