100th Infantry Battalion

100th Infantry Battalion
The Institute of Heraldry · Public domain · source
Unit name	100th Infantry Battalion
Caption	Shoulder sleeve insignia of the 100th Infantry Battalion
Dates	1942–present
Country	United States
Branch	United States Army
Type	Infantry
Size	Battalion
Garrison	Fort Shafter
Nickname	"One-Puka-Puka"
Motto	Battalion motto
Notable commanders	Col. George T. Sakato

100th Infantry Battalion The 100th Infantry Battalion is a United States Army infantry unit formed from Nisei volunteers drawn primarily from Hawaii and the mainland United States during World War II, linked to the broader history of Japanese American service in the Pacific theater. The battalion earned a reputation for combat performance during the Italian Campaign and later integrated into postwar National Guard and Regular Army structures, shaping debates around civil rights, veterans' recognition, and military policy. Its lineage connects to the 442nd Regimental Combat Team and to later Cold War and contemporary deployments, influencing memorialization in Hawaii, California, and national institutions. Historians cite the unit in studies of Executive Order 9066, Manzanar War Relocation Center, and legal challenges such as Korematsu v. United States.

Formation and Early History

The battalion was organized in 1942 following advocacy by Governor Joseph B. Poindexter, Senator Daniel Inouye's later political career being foreshadowed by service, and directives influenced by War Department personnel policies, recruiting Nisei from Territory of Hawaii, Honolulu, and internment centers like Manzanar War Relocation Center and Gila River War Relocation Center. Initial training occurred at Schofield Barracks and Camp McCoy with coordination from units such as the 24th Infantry Division and instructors from Fort Ord, while legal and civic organizations including the Japanese American Citizens League advocated for deployment. Early leadership included officers commissioned under programs connected to ROTC schools like University of Hawaii and affected by wartime measures like Executive Order 9066.

World War II Service

Deployed to the European Theatre of World War II, the battalion fought in the Italian Campaign alongside the U.S. Fifth Army, participating in operations connected to the Gothic Line and actions near Lucca, Bologna, and the Po Valley. Attached to the 34th Infantry Division and later integrated operationally with the 442nd Regimental Combat Team, the battalion gained distinction in close combat against German formations from the Wehrmacht and engagements involving Fallschirmjäger units. Command relationships involved officers with prior service in Philippine Scouts and coordination with allied formations such as the British Eighth Army and liaison with the Office of Strategic Services. The battalion's battlefield performance contributed to broader Allied advances culminating in operations linked to the Surrender of Germany.

Postwar Reorganization and Cold War Era

Following demobilization, veterans returned to Honolulu and San Francisco, influencing veterans' organizations like the American Legion and veterans' legal actions such as petitions associated with the Congressional Gold Medal process. The unit's lineage was incorporated into reserve structures including the Hawaii National Guard and reflagging within the 29th Infantry Division and elements tied to U.S. Army Pacific (USARPAC). During the Cold War, members served in capacities connected to continental defense at installations like Fort Shafter and trained alongside units from Japan Self-Defense Forces and Republic of Korea Army in bilateral exercises. Reorganization paralleled National Guard reforms enacted after the Korean War and during the Pentomic reorganization and later Army Regimental System adjustments.

Notable Engagements and Battle Honors

The battalion received praise for actions at the Rapido River sector, the Riva Ridge operations, and defensive fights in the Anzio aftermath, leading to awards for valor from commanders in the U.S. Fifth Army and recommendations to higher echelons including the War Department. The unit's members earned individual decorations such as the Medal of Honor, Distinguished Service Cross, and numerous Silver Star and Bronze Star Medal awards for actions during the Italian Campaign and subsequent European operations. Collective citations included the Presidential Unit Citation and campaign streamers for Rome-Arno, North Apennines, and Po Valley campaigns, recorded in the Order of Battle of the United States Army in World War II.

Unit Composition and Training

Originally organized as a single battalion of rifle companies with heavy weapons platoons, the unit's personnel composition drew from Nisei communities, with enlisted ranks and noncommissioned officers trained at facilities like Camp Shelby and schools overseen by the Infantry School at Fort Benning. Leadership cadres included commissioned officers from programs at ROTC units such as University of Hawaii and battlefield promotions tied to operations with the 442nd Regimental Combat Team. Tactical training emphasized mountain warfare, bocage fighting, and small-unit tactics used in engagements related to the Italian Campaign, often in coordination with allied engineers from the Royal Engineers.

Decorations and Legacy

The battalion's legacy is reflected in honors including collective Presidential Unit Citation streamers, individual Medal of Honor upgrades reviewed in postwar boards influenced by studies from the Civil Rights Movement era, and the awarding of a Congressional Gold Medal recognizing Japanese American war service. Its veterans contributed to civil litigation such as Korematsu v. United States remonstrances and to public history via partnerships with institutions like the National WWII Museum, the Japanese American National Museum, and memorials at Honouliuli and Manzanar. The unit influenced military personnel policy reforms culminating in desegregation measures following Executive Order 9981 and shaped scholarly works by historians affiliated with UCLA, Stanford University, and University of Hawaii Press.

In Popular Culture and Commemoration

The battalion has been depicted in documentaries aired by PBS, in chapters of books published by Knopf and University of California Press, and dramatized in television segments on History (U.S. TV channel) and films screened at festivals like Sundance Film Festival. Commemorative events occur at sites such as the National World War II Memorial, annual ceremonies in Honolulu and Los Angeles, and interpretive exhibits at the Japanese American National Museum and the National Museum of the Pacific War. Monuments and educational programs at Schofield Barracks and local schools preserve the battalion's history for veterans, civic leaders, and scholars from institutions including Smithsonian Institution and Library of Congress.

Category:United States Army battalions Category:Military units and formations established in 1942 Category:Japanese-American military history