The waters of the Pacific Ocean - stretching deep blue under the tropical sun, or scourged by typhoons - provided World War II's most far-flung battlefield. Two of the world's premier mid-20th century maritime powers, the United States of America and the Empire of Japan, grappled for supremacy across that pelagic expanse. In the process, they forcefully sounded the death knell of battleships and naval gunnery, ushering in the era of the aircraft carrier and the submarine.

As 1944 passed, the US Navy (USN) steadily drove the Imperial Japanese Navy (IJN) westward, closer to the Japanese home islands and defeat. Nevertheless, the IJN remained aggressive, hoping to launch a devastating attack on the American fleets to improve their nation's bargaining position, or perhaps even reverse the fortunes of war. This, of course, ignored a pair of previous catastrophic failures of similar plans, at Midway and the Battle of the Philippine Sea, otherwise known as the "Great Marianas Turkey Shoot" due to the loss of around 480 Japanese aircraft at a cost of 49 US planes.

The Americans forced the Japanese to abandon their forward base at Truk. At the same time, the USN moved its main fleet base westward, first to Eniwetok. Due to the constraints of the era's technology, plus the necessity to maintain a robust logistics chain across the Pacific's vast spaces, the island-hopping campaign represented a strategic necessity, with only the specific islands taken or bypassed open to debate.