In 1944 the Imperal Japanese Navy controlled one of the largest striking forces available to the Axis. When a census was taken of the aircraft on hand for operations on April 1, it was found that the IJN had 1,854 fighters, 930 bombers and 1,104 assorted other support aircraft. Qualitatively, many of these aircraft were superior to those produced months earlier. Starting in late 1943, the Zero Type 52 was sent to the navy in large numbers. This updated model of Japan's most famous fighter, considered its most effective variation, had been re-engineered to meet the American navy's F-6F Hellcat and F-4U Corsair carrier-based fighters. In shipping terms, the Japanese navy still retained a large fleet with an impressive mix of ships. Admiral Ozawa, who commanded the Mobile Fleet when the Battle of the Philippine Sea commenced, had nine different aircraft carriers which could launch a combined 473 aircraft. As well as the carriers, this striking force had the two largest battleships in the world (Yamato and Musashi), four other battleships, eleven excellent heavy cruisers and thirty destroyers.

The number one priority for this force of aircraft and ships was the defense of the Mariana Islands, most famously Saipan, Tinian and Guam. By way of comparison, the Japanese navy had access to many times more aircraft than the Luftwaffe had assigned to the defense of Army Group Center in the summer of 1944. The Marianas were the linchpin of Japan's defensive perimeter and had been the focus of Japanese planning for months. The Japanese navy realized that their striking force would still be smaller than the approaching American fleet possessing seven fleet aircraft carriers and eight light carriers which could launch a combined 900 aircraft. To counterbalance this inferiority, the Japanese stationed an additional 540 land-based aircraft within range of the Marianas.

On July 28, 1941 two of the most important political figures of World War II first met; Josef Stalin, dictator and warlord of the Soviet Union, and Harry Hopkins, one of the few people in the world who was trusted by Franklin Roosevelt. It was an informal meeting in Moscow that took place against the dramatic background of the ongoing German invasion of the Soviet Union. For Hopkins, it represented one of the more remarkable moments of an already remarkable career. A man both endearing and vaguely sinister, by 1941 he had become Franklin Roosevelt's second voice. Hopkins was clearly impressed with the Soviet dictator, who to him seemed both calm and knowledgeable. Stalin certainly turned on his special kind of charm and devoted a great deal of time to cultivating Hopkins. He had a personal air-raid shelter set aside for the visiting American, and made sure that it was liberally stocked with champagne, caviar, chocolates and cigarettes. Stalin also praised Roosevelt extravagantly, figuring that would please both the President and his intimate.

Hopkins had two overriding goals for the meetings. The first was to assure Stalin that Roosevelt and Winston Churchill, whom Hopkins had just left in London, were committed to supporting the Soviet Union in its life and death struggle with Nazi Germany. The second was to ask Stalin to list what the Soviet Union needed to help it resist the German invaders. The dictator was clear that the greatest threat posed by Germany was not its army – he expressed great confidence in Soviet tanks and stated that, if allowed time, Soviet numbers should prove telling. The greatest threat to the continued resistance of the USSR was the strength of the Luftwaffe. Hopkins summarized Stalin's views on the subject for Roosevelt: “He [Stalin] emphasized the fact that Germany has a strong and powerful air force, and that their present production of planes was probably between 2500 fighters and bombers per month, but not more than 3000 a month.”

Saburo Sakai was one of the most skilled fighter pilots of World War II. In 1942, when at the controls of his Mitsubishi A6M Zero (known to the Americans as the Zeke), a highly maneuverable, fast and long-ranged fighter, he reputedly shot down up to sixty American aircraft in a little more than nine months. As a member the Japanese navy, he could also count on flying with some of the best-trained and most experienced pilots to be found anywhere in the world. Two of his closest friends were Toshia Oto and Hiroyoshi Nishizawa, both among Japan's other legendary fighter aces. On August 8, 1942, however, Sakai's luck ran out. Flying out of the famous Japanese base in Rabaul, he was part of a mission sent to attack American forces which had just appeared off the island of Guadalcanal. As a round trip of 1,300 miles, this was an extremely long-range flight, even by the standards of the Zero. When Sakai reached Guadalcanal, he ended up attacking a large force of new American Avenger torpedo bombers. The tail gunner of one shattered Sakai's cockpit, causing an explosion of glass and metal which ripped into his face and body.

Remarkably, Sakai made it back to a Japanese airstrip, but was so severely wounded that he was sent home. He lost the sight in one of his eyes, so when he felt strong enough to resume duty, he was sent to train the ever-growing number of pilots that modern war demanded from Japan. By the summer of 1944, however, he felt he could no longer serve in a non-combat capacity. When it was clear that the United States was going to assault the Mariana Islands, which many Japanese realized was the linchpin of their home defense, Sakai, even with only one good eye, persuaded his superiors to allow him to return to action. Along with his good friend Nishizawa, he was charged with leading a force of thirty aircraft from the Japanese mainland to the island of Iwo Jima, from where they would be in range of Saipan and Tinian.