The Battle of Saipan was a battle of the Pacific campaign of World War II, fought on the island of Saipan in the Mariana Islands from 15 June to 9 July 1944 as part of Operation Forager. It has been referred to as the "Pacific D-Day" with the invasion fleet departing Pearl Harbor on 5 June 1944, the day before Operation Overlord in Europe was launched, and launching nine days after. The U.S. 2nd Marine Division, 4th Marine Division, and the Army's 27th Infantry Division, commanded by Lieutenant General Holland Smith, defeated the 43rd Infantry Division of the Imperial Japanese Army, commanded by Lieutenant General Yoshitsugu Saitō. The loss of Saipan, with the deaths of at least 29,000 troops and heavy civilian casualties, precipitated the resignation of Prime Minister of Japan Hideki Tōjō and left the Japanese archipelago within the range of United States Army Air Forces B-29 bombers. Background In the campaigns of 1943 and the first half of 1944, the Allies had captured the Solomon Islands, the Gilbert Islands, the Marshall Islands and the Papuan Peninsula of New Guinea. This left the Japanese holding the Philippines, the Caroline Islands, the Palau Islands, and the Mariana Islands. The Mariana Islands had not been a key part of pre-war American planning (War Plans Orange and Rainbow) because the islands were well north of a direct sea route between Hawaii and the Philippines. At the time, naval air/sea/logistics ability were not envisioned as being able to support operations against a place so far from potential land-based support. But, by early 1943, Admiral Ernest King, Commander in Chief of the United States Fleet, had become increasingly convinced of the strategic location of the islands as a base for submarine operations and air facilities for Boeing B-29 Superfortress bombing of the Japanese home islands. From these latter bases, communications between the Japanese archipelago and Japanese forces to the south and west could be cut. From the Marianas, Japan would be well within the range of an air offensive relying on the new B-29 with its operational radius of . The capture of the Marianas was formally endorsed in the Cairo Conference of November 1943. The plan had the support of U.S. Army Air Force planners because the airfields on Saipan were large enough to support B-29 operations, within range of the Japanese home islands, and unlike a China-based alternative, was not open to