Asian-Pacific Americans in the U.S. Army
100th Infantry Battalion in World War II

The 100th Infantry Battalion (Separate) was activated on 12 June 1942, composed of more than 1,400 American-born Japanese called "Nisei" (NEE-say), or second generation. The War Department had removed them from Hawaii out of fear of renewed Japanese attacks. The War Department had also stopped accepting Nisei for military service. The battalion commander and some of the company-grade officers were Caucasian; the rest of its officers and enlisted men were Nisei. After training at Camp McCoy, Wisc., and Camp Shelby, Missippi, the battalion deployed to the Mediterranean in August 1943.

Fifth Army attached the battalion to the 34th Infantry Division. The unit entered combat on 27 September 1943, near Salerno in Southern Italy. The battalion fought well and took heavy casualties. Impressed with the valor of the Hawaiian Nisei (including six awards of the Distinguished Service Cross in the first eight weeks of combat), the War Department recommended that more Nisei be recruited for an all-volunteer Nisei combat unit, the 442d Regimental Combat Team (RCT), activated on 1 February 1943. Selective Service was resumed in early 1944.

The 100th Battalion fought at Cassino in January 1944, and later accompanied the 34th Infantry Division to Anzio. In May and June 1944 the battalion, joined by the 442d RCT, helped break out from Anzio and push the Germans north of Rome. The battalion was awarded the Distinguished Unit Citation (DUC) [later redesignated the Presidential Unit Citation (PUC)] for its actions on June 26-27. On 10 August 1944, the 100th Battalion formally became part of the 442d RCT.

In September 1944 the 442d RCT was reassigned to Seventh Army for the invasion of Southern France. It was attached to the 36th Infantry Division for the drive into the Vosges Mountains. In four weeks of heavy combat in October-November 1944, the 442d RCT, including the 100th Battalion, liberated Bruyeres and Biffontaine and rescued a "lost battalion" that had become cut off from the 36th Division. For this the 100th Battalion received its second DUC.

As draftees gradually replaced combat losses, the battalion lost some of its character as an all-Hawaiian unit. After duty in the Maritime Alps guarding the French-Italian border, the 442d RCT was reassigned in March 1945 to Fifth Army for the Po Valley campaign. Attached to the 92d Infantry Division, an African-American unit, the 442d RCT helped drive the Germans from Northern Italy. On 5 April, the first day on the attack, Pfc. Sadao S. Munemori from Los Angeles gave his life to protect two buddies in Company A, 100th Battalion, and was awarded the Medal of Honor posthumously.

The 442d RCT was demobilized and inactivated in August 1946. The lineage and honors have been preserved by the 100th Battalion, 442d Infantry (US Army Reserve).

For further information, see the following:

  • Crost, Lyn. Honor by Fire: Japanese Americans at War in Europe and the Pacific. Novato, Calif., 1994.
  • Duus, Masayo. Unlikely Liberators: The Men of the 100th and 442nd. Honolulu, 1987.
  • Murphy, Thomas D. Ambassadors in Arms: The Story of Hawaii's 100th Battalion. Honolulu, 1954.
  • Shirey, Orville C. Americans: The Story of the 442d Combat Team. Washington, 1946.
  • Takaki, Ronald. Strangers from a Different Shore: A History of Asian Americans. Boston, 1989.
  • Tanaka, Chester. Go For Broke. San Francisco, 1982.

Prepared 16 May 2000
by James C. McNaughton
Command Historian
Defense Language Institute
Foreign Language Center, Presidio of Monterey