<P> Most Japanese forces in the theater were part of the Combined Fleet (聯合 艦隊, Rengō Kantai) of the Imperial Japanese Navy (IJN), 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 (1943--44) and Admiral Soemu Toyoda (1944--45). The General Staff (参謀 本部, Sanbō Honbu) of the Imperial Japanese Army (IJA) 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 operational level, and their command structures / geographical areas of operations overlapped with each other and those of the Allies . </P> <P> In the Pacific Ocean theater, Japanese forces fought primarily against the United States Navy, the U.S. Marine Corps and the U.S. Army . The United Kingdom, New Zealand, Australia, Canada and other Allied nations also contributed forces . </P> <Ul> <Li> Central Pacific Theater <Ul> <Li> Attack on Pearl Harbour 7 December 1941 </Li> <Li> Battle of Wake Island 7--23 December 1941 </Li> <Li> Doolittle Raid 18 April 1942 </Li> <Li> Battle of the Coral Sea 4--8 May 1942 </Li> <Li> Battle of Midway 4--7 June 1942 </Li> <Li> Guadalcanal Campaign 7 August 1942 to 9 February 1943 </Li> <Li> Gilbert and Marshall Islands campaign 1943--44 <Ul> <Li> Makin Island raid 17--18 August 1942 </Li> <Li> Battle of Tarawa 20 November 1943 </Li> <Li> Battle of Makin 20--23 November 1943 </Li> <Li> Battle of Kwajalein 14 February 1944 </Li> <Li> Battle of Eniwetok 17 February 1944 </Li> </Ul> </Li> <Li> Attack on Truk Island 17--18 February 1944 </Li> <Li> Mariana and Palau Islands campaign 1944 <Ul> <Li> Battle of Saipan 15 June 1944 </Li> <Li> Battle of the Philippine Sea 19--21 June 1944 </Li> <Li> Battle of Guam 21 July 1944 </Li> <Li> Battle of Tinian 24 July 1944 </Li> <Li> Battle of Peleliu 15 September 1944 </Li> <Li> Battle of Angaur 17 September 1944 </Li> </Ul> </Li> <Li> Battle of Leyte 20 October 1944 <Ul> <Li> Battle of Leyte Gulf 23 October 1944 </Li> </Ul> </Li> <Li> Battle of Iwo Jima 19 February 1945 </Li> <Li> Battle of Okinawa 1 April 1945 </Li> </Ul> </Li> <Li> North Pacific Theater <Ul> <Li> Aleutian Islands Campaign 1942--43 </Li> <Li> Battle of the Komandorski Islands 26 March 1943 </Li> </Ul> </Li> </Ul> <Li> Central Pacific Theater <Ul> <Li> Attack on Pearl Harbour 7 December 1941 </Li> <Li> Battle of Wake Island 7--23 December 1941 </Li> <Li> Doolittle Raid 18 April 1942 </Li> <Li> Battle of the Coral Sea 4--8 May 1942 </Li> <Li> Battle of Midway 4--7 June 1942 </Li> <Li> Guadalcanal Campaign 7 August 1942 to 9 February 1943 </Li> <Li> Gilbert and Marshall Islands campaign 1943--44 <Ul> <Li> Makin Island raid 17--18 August 1942 </Li> <Li> Battle of Tarawa 20 November 1943 </Li> <Li> Battle of Makin 20--23 November 1943 </Li> <Li> Battle of Kwajalein 14 February 1944 </Li> <Li> Battle of Eniwetok 17 February 1944 </Li> </Ul> </Li> <Li> Attack on Truk Island 17--18 February 1944 </Li> <Li> Mariana and Palau Islands campaign 1944 <Ul> <Li> Battle of Saipan 15 June 1944 </Li> <Li> Battle of the Philippine Sea 19--21 June 1944 </Li> <Li> Battle of Guam 21 July 1944 </Li> <Li> Battle of Tinian 24 July 1944 </Li> <Li> Battle of Peleliu 15 September 1944 </Li> <Li> Battle of Angaur 17 September 1944 </Li> </Ul> </Li> <Li> Battle of Leyte 20 October 1944 <Ul> <Li> Battle of Leyte Gulf 23 October 1944 </Li> </Ul> </Li> <Li> Battle of Iwo Jima 19 February 1945 </Li> <Li> Battle of Okinawa 1 April 1945 </Li> </Ul> </Li>

Where was the first major pacific battle in wwii
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