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100th Infantry Battalion Guide for Publication and Project Development

The 100th Infantry Battalion Veterans (Club 100) was incorporated by the veterans in December 1945, in part, to perpetuate the identity of the 100th Infantry Battalion, develop and maintain appropriate records of its heroic achievements, and, as its Charter of Incorporation states, generally to do all lawful things that reasonably may assure that the sacrifices made in combat by the veterans and by their comrades who died on the field of battle in the cause of liberty and justice shall not have been made in vain.


100th Infantry Battalion veterans from the 1st Draft of December 1940 pose for a group photo at the Clubhouse.

100th Infantry Battalion veterans from the 1st Draft of December 1940, pose for a group photo at the 100th Inf Bn Veterans (Club 100) Clubhouse, 50 years later, in December 1990.


Today, the 100th Infantry Battalion Veterans organization continues to represent the men who served in the 100th Infantry Battalion in World War II, composed largely of Americans of Japanese ancestry from Hawai‘i. We strive to support initiatives to accurately portray the 100th Infantry Battalion in publications and projects, and appreciate the involvement and support from the community, to continue to ensure that the identity of the 100th Infantry Battalion is preserved, and its legacy honored.


Essential Guide to the 100th Infantry Battalion


We have put together the following essential guide to the 100th Infantry Battalion, based on the three questions that we have been asked most when working with various project teams and publications over the decades.


 

When were the 100th Infantry Battalion and the 442nd Regimental Combat Team formed?


The 100th Infantry Battalion (Separate) was activated on June 12, 1942.


Following the “Selective Training and Service Act of 1940” being signed into law in the United States in September 1940, the Hawai‘i National Guard units of the 298th and 299th Infantry Regiments were activated and federalized under the U.S. Army command on October 15, 1940. The majority of these men were drafted, and about half of the men inducted in Hawai‘i were Americans of Japanese ancestry (AJA).


During the attack on Pearl Harbor on December 7, 1941, the men of the Hawai‘i National Guard were on duty, and protecting the shorelines.

 

On January 5, 1942, the War Department reclassified Japanese Americans as "4-C, enemy aliens," and no longer eligible to be drafted into military service. However, the AJA men who were already serving continued to carry out their orders to protect the people of Hawai‘i.

100th Inf Bn Unit History (NARA RG407-b21085)
100th Inf Bn Unit History (NARA RG407-b21085)

As a battle at Midway Island appeared likely, it was feared that Hawai‘i would become Japan's next target. On May 28, 1942, AJA men from the 298th and 299th Infantries, engineer battalions, activated reservists, and regular Army, were gathered at Schofield Barracks. The men were placed into a newly formed “Hawaiian Provisional Infantry Battalion.” With the exception of a few Caucasian officers and about 20 men of Hawaiian and other Asian ethnicities (including those who were of mixed ethnicities), it was the first segregated Japanese American military unit.


This newly formed Hawaiian Provisional Infantry Battalion was to leave Hawai‘i on the first available transport. The men were told that they were being sent somewhere on the mainland to train, and were ordered to keep the information secret from their families.

 

On June 5, 1942, these 1,432 officers and enlisted men boarded an old converted U.S. Army transport ship called the "Maui," and quietly departed Honolulu in much secrecy, during a time of uneasiness as the Battle of Midway commenced. There was no announcement of their departure in the newspapers or on the radio.

 

100th Inf Bn Activation (NARA RG407-b21085)
100th Inf Bn Activation (NARA RG407-b21085)

The boat docked in Oakland, California, on June 12, 1942. There, the unit was officially activated and redesignated the “100th Infantry Battalion (Separate).” It was an “orphan battalion,” not assigned to any larger army unit.


Under this name, the men of the 100th underwent 14 months of extensive military training in Wisconsin, Mississippi, and Louisiana from June 1942 until August 1943, as the government and military officials observed their performance while determining what to do with these AJA soldiers.


From April 1943 through June 1943, the 100th was sent on advanced field maneuvers at Camp Claiborne in Louisiana. Through their performance, the men of the 100th Infantry Battalion demonstrated that they were fully qualified for combat.



The 442nd Regimental Combat Team was activated on February 1, 1943.


In January 1943, largely due to the excellent record of the 100th Infantry Battalion (Separate) during their extensive military training on the mainland, plus the service of the “Varsity Victory Volunteers” in Hawai‘i, the War Department announced plans to organize an all-volunteer Japanese American army unit. The Varsity Victory Volunteers in Hawai‘i requested the deactivation of their unit so its members could enlist in the new unit. The unit was named the “442nd Regimental Combat Team,” and was activated on February 1, 1943 by President Franklin D. Roosevelt.

 

At the time, on the U.S. mainland, there were approximately 19,000 AJA men of military age in the incarceration camps and approximately 4,000 outside of the camps. In comparison, there were approximately 25,000 AJA men of military age in the Territory of Hawai‘i.

 

With the 1,432 men from Hawai‘i already serving in the 100th Infantry Battalion (Sep), the U.S. Army called for 1,500 AJA volunteers from Hawai‘i — around 10,000 responded. In comparison, a quota of 3,000 AJA volunteers was established on the mainland, but the response was only about 1,200 – an indication of how the mass incarceration of the Japanese American community on the mainland had influenced their enthusiasm to join the U.S. Army to fight for America. Eventually, the 442nd RCT was organized in March 1943 with about two-thirds (2/3) of the men inducted from Hawai‘i , and one-third (1/3) from the U.S. mainland.

 

On March 28, 1943, the Honolulu Chamber of Commerce sponsored a large farewell ceremony with over 15,000 spectators at ‘Iolani Palace, for the initial 2,686 AJA volunteers of the 442nd RCT from Hawai‘i. This was a stark contrast to the solemn manner in which the 1,432 men of the 100th Infantry Battalion (Separate), then known as the Hawaiian Provisional Infantry Battalion, had quietly departed in secrecy on June 5, 1942.

 

The men of the 442nd RCT from Hawai‘i departed on April 4, 1943 for Camp Shelby. The inductees from the mainland had already begun to arrive at Camp Shelby, Mississippi, and the 442nd RCT began their basic training at Camp Shelby.


While it is true that most of the mainland soldiers came from the incarceration camps, it must be remembered that Hawai‘i provided almost all of the soldiers in the 100th Infantry Battalion (Separate), as well as 2/3 of the soldiers in the original 442nd Regimental Combat Team. Fewer than 2,000 out of nearly 160,000 residents of Japanese descent in Hawai‘i were interned.



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When did the 100th Infantry Battalion and the 442nd Regimental Combat Team combine?


The 100th Infantry Battalion (Separate) was officially redesignated as the 100th Battalion, 442nd Infantry on August 10, 1944.


The 100th Infantry Battalion first met up with the 442nd RCT upon its return to Camp Shelby, Mississippi, from advanced training in Louisiana. The men of the 442nd RCT had arrived at Camp Shelby while the 100th was away on maneuvers, and had begun basic training.


100th Infantry Battalion Colors with motto, "Remember Pearl Harbor."
100th Infantry Battalion Colors with motto.

On July 20, 1943, the 100th Infantry Battalion (Sep) received its battalion colors, which included its Coat of Arms, motto “Remember Pearl Harbor,” and unit’s name, “One-Hundredth Infantry Battalion (Sep).”


The 100th departed Camp Shelby by train on August 11, 1943, arriving in Camp Kilmer, New Jersey, and was then transported by train, to New York. The 100th headed to Staten Island, boarded the “S.S. James Parker,” and began their 12-day voyage to Oran, Algeria in North Africa, on August 21, 1943. Attached to the 133rd Infantry Regiment, 34th Infantry Division (ID), commanded by Major General Charles W. Ryder in Oran, the 100th Infantry Battalion and the 34th Infantry Division sailed together to Italy on September 19, 1943, landing at Salerno.


The 100th Infantry Battalion (Separate) became the first AJA (Americans of Japanese ancestry) World War II unit to engage in combat in the European-African-Middle Eastern theater. It headed into combat on the night of September 26, 1943, carrying out its orders in pursuit of retreating German forces through muddy terrain and rain. Together with the 34th ID, the men fought their way north through the tough battles of the Naples-Foggia, Anzio, and Rome-Arno campaigns, and suffered tremendous casualties.


The 100th landed in Salerno in September 1943 with about 1,300 men, but by the end of February 1944, its effective strength was reported to be about 460 men.


January 1944 announcement regarding Reinstitution of Draft of AJA
Selective Service reinstitution for Japanese Americans.

Having been depleted by the transfer of men to the other companies due to the tremendous number of casualties suffered by the 100th Infantry Battalion, Companies E and F were officially inactivated by mid-December 1943.


In January 1944, the first group of officers and enlisted men from the 442nd RCT was transferred to be replacements in the 100th Infantry Battalion (Sep), and a second and third group followed. These replacements joined the 100th Infantry Battalion in March to May 1944.


With a growing need for manpower for the segregated units of the 100th Infantry Battalion (Sep) and 442nd RCT, Selective Service induction of AJA resumed in January 1944. With this, the U.S.-born Nisei and Sansei AJA were no longer labelled "enemy aliens," and were considered suitable to be drafted into military service and engage in combat.


When the 442nd RCT arrived in Italy, the 100th Infantry Battalion (Sep) was attached to the regiment on June 11, 1944, serving the role of its 1st Battalion. The unit was officially redesignated as the 100th Battalion, 442nd Infantry on August 10, 1944.


August 1944 Redesignation to 100th Battalion 442nd Infantry
Redesignation to 100th Bn, 442nd Infantry (Aug 1944).
Memo dated June 24, 1944 from Assistant Secretary of War John McCloy regarding the retaining of the 100th's numeric unit designation.
Memo from Asst. Sec. of War John McCloy, regarding retaining of 100th unit designation.

The 100th had been in combat for over 10 months by that point, and a General Order was issued by the Fifth Army, to allow the unit to retain its “100th” numeral designation, due to its pioneering role as a Japanese American battalion, and outstanding combat record.



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How many awards were earned by the 100th/442nd?


The 100th Infantry Battalion (Sep) and 442nd Regimental Combat Team (including the 100th Bn) were awarded over 4,000 Purple Heart Medals.

At war's end, the 100th Infantry Battalion was recorded to have been awarded 1,703 Purple Heart medals.


Though at times, the 100th/442nd has been noted to have earned 9,485 Purple Hearts, this number incorrectly includes over 5,000 non-battle casualties such as frostbite, trench foot, and illnesses. The correct Purple Heart medals count is over 4,000 which is consistent with the Battle Casualties provided by the U.S. Army Mediterranean Theater of Operations Information-Education Section. The Story of the 442nd Combat Team, Composed of: 442nd Infantry Regiment, 522nd Field Artillery Battalion, 232nd Combat Engineer Company, 1945. (http://the442.org/442ndfacts.html). Major organizations and websites with a focus on the Japanese American units and history, all recognize and use the corrected over 4,000 Purple Hearts figure.


Together with the 100th Infantry Battalion, the 442nd Regimental Combat Team is the most decorated unit for its size and length of service, in U.S. military history.


Percentage in the 100th Inf Bn who died prior to its redesignation to the 442nd RCT.
Percentage in the 100th Inf Bn who died prior to its redesignation to the 442nd RCT.

The 100th Infantry Battalion (Sep) fought in combat from September 1943 to June 1944, for nearly 9 months before the 442nd RCT arrived in Italy.


Since the decorations and awards that the 100th earned prior to its redesignation as the 100th Bn, 442nd Inf in August 1944 are included in the totals of the 442nd RCT, it

Number of AJAs who died in WWII by "Hometown"
Number of AJAs who died in WWII by "Hometown"

is only proper to state that the 442nd RCT, including the 100th Infantry Battalion, is considered the most decorated unit in U.S. military history, for its size and length of service.


For a comprehensive listing of statistics, awards, and decorations of the 100th/442nd, please visit our References page here:






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Still have questions?


Please visit our 100th Infantry Battalion Veterans Education Center online at https://www.100thbattalion.org/ for our extensive collection of photos, memoirs, articles, and information on the 100th Infantry Battalion.


For further questions on research on the 100th Infantry Battalion, please contact our 100th Infantry Battalion Veterans (Club 100) Clubhouse office at (808) 946-0272 or info@100thibv.org

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