Finally, there were lessons learned from the supply confusion that had marred the early days on the beaches and hadn’t improved much since the days of the Guadalcanal landing. Logistic problems had arisen because, once a beach was in friendly hands, the ships were unloaded as rapidly as possible and the sailors in the landing craft were in a hurry to get into the beaches and back out again. Supplies were spread all over the beach, partly because of the enemy’s artillery and mortar harassing fire on the beaches, but also because of the corps’ hard-driving, rapid attack, the estimate of resupply requirements was far too small. For example, a shortage of radio batteries was never corrected. There was insufficient time to sort and separate equipment and supplies adequately. Consequently, there were mix-ups, with Marine uniforms getting into Army dumps and Army supplies showing up in Marine dumps.
It was after the beach confusion at Saipan that the Navy decided a permanent corps shore party should be organized. It would be solely responsible for the movement of all supplies from the beach to the dumps and for the subsequent issue to the divisions.
Tactical lessons learned were also new to the Central Pacific war. Instead of a small atoll, the battle had been one of movement on a sizable land mass, and it was further complicated by the numerous caves and the defensive systems they provided for the Japanese. The enemy had defended caves before, but never on such a large scale. On Saipan, these caves were both natural and man-made. Often natural vegetation gave them excellent camouflage. Some had steel doors which could be opened for an artillery piece or machine gun to fire, and then retreat behind the door before return fire could take effect. The flame-throwing tanks could reach many of these caves and so proved very useful. Unfortunately, their range was limited on Saipan, but this was later improved.
Thus it was that the hard experiences on Saipan led to a variety of changes which paid valuable dividends in saving American lives in the future Pacific campaigns. And the loss of the island was a strategic strike from which the Japanese never recovered, as the United States drove forward to ultimate victory.
Sources
There are five principal official sources for the facts about the unit actions on Saipan. These range from preliminary, condensed accounts to massive, detailed final studies which reach down to the level of company operations. In the interests of brevity, the author of this monograph has limited himself to covering the actions of regiments and divisions, with minor special exceptions.
The five sources are:
1) Henry I. Shaw, Jr., Bernard C. Nalty, and Edwin T. Turnbladh, Central Pacific Drive, vol. 3, History of U.S. Marine Corps Operations in World War II (Washington: Historical Branch, G-3 Division, Headquarters, U.S. Marine Corps, 1966).
2) Philip A. Crowl, Campaign in the Marianas, vol 9, United States Army in World War II, The War in the Pacific (Washington: Office of the Chief of Military History, Department of the Army, 1960).
3) Maj Carl W. Hoffman, USMC, Saipan: The Beginning of the End (Washington: Historical Division, Headquarters, U.S. Marine Corps, 1950).