The attacks on Hiroshima and Nagasaki in early August hastened Japan’s decision to come to terms with the Allies. All plans for the invasion of Japan were cancelled while new plans for the occupation of the home islands were drawn up. Preliminary preparations, however, were formulated prior to Japan’s acceptance of the terms of the surrender on 14 August.
Three days before, 11 August, Task Force A was organized with Brigadier General William T. Clement as its commanding officer. This unit was one of the first to be assigned a role in the occupation. Its prime objective was the seizure of the large naval base at Yokosuka in Tokyo Bay. At the time of the creation of the task force the 6th Marine Division was directed to supply one regimental combat team for the occupation. General Shepherd unhesitatingly selected the 4th Marines. This was a symbolic gesture designed to avenge the capture of the 1’old” 4th on Corregidor. The “new” 4th, in effect, vindicated the “old” 4th by becoming the first American combat unit to land in Japan.
The 4th Marines quickly readied itself for its new assignment and then sailed from Guam on 15 August. Fifteen days later it was on Japanese soil. Units of the occupation force were transferred to landing craft on the morning of the 30th for the trip ashore. Half expecting treachery from the Japanese, the Marines were prepared to meet any eventuality including armed opposition.
First ashore was the 2d Battalion, landing on Futtsu Cape shortly before 0600. Personnel of this unit were the first American combat troops to set foot in Japan and, thus, the first foreign invader to ever touch the Japanese mainland. The battalion rapidly made sure that the guns on the cape which guarded the approaches to Tokyo Bay were inoperable. The battalion, after accepting the surrender of the garrison, reembarked to become the reserve for the main landings at Yokosuka which were underway by this time.
Both 1/4 and 3/4 had come ashore at 0930 with the latter occupying the naval base while the former seized the airfield. Demilitarization of all installations was begun immediately. As in the case of the first landing, the later landings were unopposed, with Japanese military officials cooperating with the Marines to the fullest extent.
The occupation plan was promptly executed, so much so that Task Force A was disbanded on 21 September 1945. All 6th Marine Division units were withdrawn with the exception of the 4th Marines. Primary duties for the regiment in the fall of 1945 were maintaining perimeter defense for the Yokosuka Naval Base, providing an interior guard for the base, and the continued disarming of Japanese forces.
By November, the regiment began to feel the first effects of postwar demobilization which was then in progress. Administrative control of the 4th Marines on the 20th passed to Headquarters, Fleet Marine Force, Pacific. Two weeks later, 1/4 was ordered to Camp Pendleton, California, where it was deactivated on 29 December. All remaining elements of the regiment except a part of Headquarters and the 3d Battalion sailed from Japan on 1 January 1946. The complete withdrawal of the 4th Marines from the occupation of Japan took effect on 15 February when the 3d Battalion was deactivated at Yokosuka.