 On 15 July 1938 he was promoted to major general, and assigned command of the IJA 6th Infantry Brigade.As lieutenant general and commander of the IJA 2nd Division, Maruyama and his division were deployed to Guadalcanal from September and October, 1942 in response to the Allied landings on the island.During the resulting Guadalcanal campaign, Maruyama led troops during the October 1942 Matanikau action and the subsequent Battle for Henderson Field, in which Maruyama's troops were decisively defeated.