U.S. 100th Infantry Battalion

100th Infantry Battalion
442nd Infantry Regiment distinctive unit insignia worn by the 100th Infantry Battalion
Active	1942–1946 1947–present
Allegiance	United States of America
Branch	United States Army
Type	Separate infantry battalion
Garrison/HQ	Fort Shafter
Nickname(s)	"Purple Heart Battalion" "One-Puka-Puka"
Motto(s)	Go for Broke
Engagements	World War II Iraq War
Decorations	Presidential Unit Citation (Army) (4) Meritorious Unit Commendation (Army)
Commanders
Current commander	LTC Ken Tafao
Command Sergeant Major	CSM Joshua Mason
Insignia
Combat service identification badge

The 100th Infantry Battalion is the only infantry unit in the United States Army Reserve. In World War II, the then-primarily Nisei battalion was composed largely of former members of the Hawaii Army National Guard. The 100th saw heavy combat during World War II before and after combining with the 442nd Infantry Regiment, another mostly Nisei military unit, into a single fighting combat team. Based at Fort Shafter, Honolulu, Hawaii, the 100th Battalion has reservists from Hawaii, American Samoa, Guam and Saipan, and has deployed to Iraq and Kuwait. The unit was unofficially nicknamed the "Purple Heart Battalion", with the motto "Remember Pearl Harbor".

On the morning 7 December 1941, the United States was attacked by the Empire of Japan, marking the beginning of World War II for the United States. After the attack, Japanese-Americans and those of Japanese descent faced prejudice at home. Chaos ensued in the hours that followed the Pearl Harbor attack, but the 298th and 299th Hawaii National Guard prepared for an invasion, cleared the rubble, donated their blood, and aided the wounded. However, three days after the attack, the units' rifles were stripped from them because of the ethnicity of members; eventually those rifles were returned. Nisei that were a part of the ROTC program at the University of Hawaii were discharged from the Hawaii Territorial Guard. Those former members eventually formed the Varsity Victory Volunteers.

At 11:30 a.m. martial law was declared and Governor Joseph Poindexter told President Franklin D. Roosevelt that his greatest fear was sabotage by the large Japanese population in Hawaii. The FBI rounded up known Japanese sympathizers, Buddhist priests, language school principals and teachers, civic and business leaders, fisherman, and instructors of judo and related martial arts. The War Department discharged all soldiers of Japanese ancestry, had all Japanese-Americans on the West Coast rounded up and placed in internment camps around the U. S., deactivated of the Hawaii Territorial Guard, and had all Japanese-Americans reclassified as 4-C: enemy aliens.