The Pacific Ocean theater, during World War II, was a major theater of the war between the Allies and Japan. It officially came into existence on March 30,1942, when US Admiral Chester Nimitz was appointed Supreme Allied Commander Pacific Ocean Areas. In the other theatre in the Pacific region, known as the South West Pacific theatre. Both Nimitz and MacArthur were overseen by the US Joint Chiefs, most Japanese forces in the theater were part of the Combined Fleet of the Imperial Japanese Navy, which was responsible for all Japanese warships, naval aircraft, and marine infantry units. The Rengō Kantai was led by Admiral Isoroku Yamamoto, until he was killed in an attack by U. S. fighter planes in April 1943, Yamamoto was succeeded by Admiral Mineichi Koga and Admiral Soemu Toyoda. The General Staff of the Imperial Japanese Army was responsible for Imperial Japanese Army ground and air units in Southeast Asia and the South Pacific. The IJN and IJA did not formally use joint/combined staff at the level, and their command structures/geographical areas of operations overlapped each other. In the Pacific Ocean theater, Japanese forces fought primarily against the United States Navy, US Marine Corps, the United Kingdom, New Zealand, Australia, Canada and other Allied nations also contributed forces. Pacific Crucible, War at Sea in the Pacific, 1941–1942, the Official Chronology of the U. S. Navy in World War II. In the Service of the Emperor, Essays on the Imperial Japanese Army, a History of Us, War, Peace and all that Jazz. Kafka, Roger, Pepperburg, Roy L. Warships of the World, the Campaigns of the Pacific War
Japanese naval aircraft prepare to take off from an aircraft carrier.
U.S. 5th Marines evacuate injured personnel during actions on Guadalcanal on November 1, 1942.