The 51st Division was an infantry division of the Imperial Japanese Army. Its call sign was the Base Division . It was formed on 10 July 1940 at Utsunomiya, Tochigi, simultaneously with 52nd, 54th, 55th, 56th, and 57th divisions. The 51st Division was initially assigned to the Eastern District Army and placed under command of Lieutenant General Kenichiro Ueno.

The 56th Division was an infantry division of the Imperial Japanese Army. Its call sign was the Dragon Division . It was formed on 10 July 1940 in Kurume, simultaneously with the 51st, 52nd, 54th, 55th, and 57th Divisions. The formation nucleus was the headquarters of the 12th Division. Its manpower came primarily from Fukuoka, Saga and Nagasaki prefectures. The 56th Division was initially assigned to the Kurume Mobilization District, under the command of the Western District Army.