The 100th Infantry Battalion was formed after the attack on Pearl Harbor, during a period of turmoil and fear in the Territory of Hawaii. The 100th was made up almost entirely of Nisei, second generation Americans of Japanese Ancestry (AJAs), who had learned traditional Japanese values at home and American principles of democracy at school. Young Nisei men had demonstrated their willingness to serve their country well before the attack, comprising nearly half of the 298th and 299th Infantry Regiments of the Hawaii National Guard.
The 442nd Regimental Combat Team (RCT) was formed in February 1943, with 4,500 volunteer Americans of Japanese ancestry (AJAs). Two-thirds were from Hawaii, the rest from the Mainland, where many of their families had been forced out of their homes and relocated to internment camps.
More than 6,000 Americans of Japanese ancestry (AJAs) – about half of them from Hawaii – served in the Army’s Military Intelligence Service (MIS) during World War II. Using their knowledge of the enemy’s language and culture, the MIS is credited with saving countless lives and shortening the war immeasurably.
The 1399th Engineer Construction Battalion was established at Schofield Barracks in April 1944 as part of the Central Pacific Base Command. Soldiers of the previously activated 370th Engineer Battalion (Special Services) made up the nucleus of the new battalion. Americans of Japanese Ancestry (AJAs) soldiers from the Selective Service draft in the summer of 1944 were assigned to the 1399th. The 1536th Dump Truck and 1525th Base Equipment companies were added to work with the 1399th.