 On June 3, 1940, the Guards Mixed Brigade became the 1st Guards Brigade of the 1st Guards Division.The 2nd Imperial Guards Infantry Regiment under Col. Kunio Osonoe from 1st Guards Brigade was assigned to the Indochina Expeditionary Army in September, 1940.In October 1940, the remainder of 1st Guards Brigade (1st Guard Regiment and support units) joined other Japanese units occupying French Indochina.