In terms of quantity and quality of aircraft, as well as pilot training and experience, the Americans outmatched the Japanese carrier forces under Ozawa's command.

Promoted to lieutenant commander on December 1, 1921, he embarked on the destroyer Take, then joined the staff of the Mako Guard District in the Pengu Islands.

Admiral Nishizō Tsukahara would say that: "He (Nagumo) was wholly unfitted by background, training, experience, and interest for a major role in Japan’s naval air arm.

Vice-Admiral Ozawa was appointed as Commander-in-Chief of the Southern Expeditionary Fleet on October 18, 1941, giving him responsibility for naval operations in the South China Sea.

Ozawa planned and successfully completed simultaneous landing operations at both Kota Bahru and Songkhla on December 8 without being intercepted by the British Eastern Fleet.

[17] The tonnage and number of ships sunk by Ozawa's force, are comparable to that of the 3-month long Operation Berlin raid conducted by two battleships of the Kriegsmarine from January to March 1941.

The IJN desperately needed to replace the heavy losses suffered by their carrier forces at Midway and the Battle of the Santa Cruz Islands.

After the massive American air attacks on Rabaul in November 1943 and on Truk in February 1944, the 3rd Fleet withdrew to safer anchorage of the Lingga Islands in Sumatran waters, near Singapore.

While Chitose was at sea off Tawi-Tawi, conducting air training on 22 May 1944, the American submarine USS Puffer fired a spread of torpedoes at her, but they exploded in her wake and she escaped damage.

At the end of May 1944, as the 1st Mobile Fleet anchored at Twai-Twai, Vice-Admiral Ozawa was forced to prohibit training sorties on the open ocean.

By then American bombardments had begun on the Mariana Islands, triggering Plan A-Go, and Vice Admiral Ugaki was ordered to sail the 1st Mobile Fleet, which was on its way west from Saipan, to the Philippine Sea on June 17.

[37] On the evening of June 18, the 1st Mobile Fleet was detected by American submarines, and Admiral Nimitz was able to locate it 560 km west-southwest of Saipan.

Despite the efforts of the damage control teams, the carriers sank in part due to the volatility of the poor-quality aviation fuel that the Japanese were forced to use.

The Japanese defeat in the Philippine Sea made the loss of the Mariana Islands inevitable, which brought the heart of the Empire of Japan within range of the United States Army Air Forces' long-range B-29 Superfortress bombers.

[46] Vice-Admiral Ozawa then reported to Admiral Toyoda, Commander-in-Chief of the Combined Fleet, of the impossibility for the crews of his aircraft carriers being ready in time to provide air cover for Kurita's force.

During the night, warned that Vice-Admiral Kurita's Force had been spotted entering the San Bernardino Strait, Admiral Halsey did not worry.

The attack did not take place until around 8:40 a.m. To the surprise of American airmen, the Japanese carriers had no aircraft on the flight decks, and virtually no fighter cover.

Task Force 38 had taken the bait and was in contact with the Japanese aircraft carriers, TF38 was north of Luzon, 200 nautical miles away from the San Bernardino Strait.

However, Halsey continued to advance north, with his flagship, USS New Jersey, the modern battleships under Vice Admiral Lee and the large cruisers.

At 11:15 a.m., when the immobilized Japanese ships were only 40 nautical miles away, he ordered the fast battleships to turn south, in an attempt to intercept Kurita's force.

Around 7:30 p.m., learning of DuBose's relatively weak task group, Vice-Admiral Ozawa decided to turn around with his two battleships and meet the outgunned American forces.

In planning the operation, the navy partnered with Lieutenant-General Shirō Ishii of Unit 731, who had extensive experience on weaponizing pathogenic bacteria and human vulnerability to biological and chemical warfare.

The planes would spread weaponized bubonic plague, cholera, typhus, dengue fever, and other pathogens in a biological terror attack upon the population.

[67][68][69][70] Planning for Operation PX was finalized on March 26, 1945, but shelved shortly thereafter due to strong opposition from Army Chief of General Staff Yoshijirō Umezu.

[71] In February 1945, with the formation of the 5th Air Fleet, under Vice Admiral Matome Ugaki, navy high command began to supervise kamikaze operations.

Feeling pressured by the emperor to mount some kind of attack, Japanese Navy high command conceived a kamikaze-type mission for their remaining operational large ships.

[73] Ozawa was involved in the planning of Operation Ten-Go, code name of the suicide attack of battleship Yamato, cruiser Yahagi and eight other warships against Allied forces engaged at Okinawa.

As commander of the Combined Fleet, he continued Operation Kikusui, a series of kamikaze attacks launched against Allied naval forces around Okinawa.

[77] The operation was a suicide attack in which Yokosuka P1Ys would strafe and bomb American airfields in the Mariana Islands, afterwards, Mitsubishi G4Ms carrying Giretsu Kuteitai commandos would crash land on them.

[80] Submarine carriers I-400 and I-401 then were to launch a combined total of six M6A1 floatplanes — which were to use the reconnaissance information to assist them in targeting Allied ships — on 17 August 1945 for a nighttime strike under a full moon against the Ulithi anchorage, each plane armed with an 800-kilogram (1,764 lb) bomb.