Initially, Yokoi served with the 29th Infantry Division in Manchukuo. In 1943, he was transferred to the 38th Regiment in the Mariana Islands and arrived on Guam in February 1943. When American forces captured the island in the 1944 Battle of Guam, Yokoi went into hiding with nine other Japanese soldiers.[2] Seven of the original ten eventually moved away and only three remained in the region.