On May 26, 1942, General George C. Marshall issued orders establishing the Hawaiian Provisional Battalion. On June 5th, the Hawaiian Provisional Battalion consisting of 1300 men and 29 officers, under the command of Lt. Col. Farrant Turner, sailed for the mainland and training. The Hawaiian Provisional Battalion landed in Oakland, California on June 10, 1942. Two days later the 100th Infantry Battalion was activated, or better known as "the One Puka Puka." The 100th Infantry battalion was assigned to the Second Army shortly after their arrival at Camp McCoy. 

The 100th had their basic training from June to December. Most of them had already gone through these tests when they were part of the National Guard or Territorial Guard, so doing it again seemed a waste of time. However, not wanting to give the Army any excuse into sending them back they completed their basic training with superior ratings in the field and on the drill grounds. They also earned five Soldier's Medals for heroism while not in combat for saving the lives of several local residents who almost drowned in a frozen lake. 

The Army and the government still didn't have too much trust in the "guinea pigs from Pearl Harbor", and had several people keeping an eye on them during this time. All the officers of the 100th Battalion, and later the 442nd RCT, were haole (Hawaiian for white) and most had some background in psychology or were picked to keep tabs on the army's new recruits. 

In February of 1943, the 100th Battalion was transferred from Camp McCoy to Camp Shelby, Mississippi for advanced-unit training. They were now attached to the 69th Division. The 100th scored top scores and received a two-week rest period. Because of their excellent training record the decision was made to open the draft to all Japanese-Americans. In the nine months that the 100th Battalion existed President Franklin D. Roosevelt and the War Department were forced by the steady stream of petitions and interventions by prominent Americans, both civilian and military, to re-open military service to Americans of Japanese ancestry. 

The 442nd RCT consisted of the following units: 442nd Headquarters Company, Anti-tank Company, Cannon Company, Medical Detachment, Service Company, 100th Battalion(Company HQ, A, B, C, D), 2d Battalion(Company E-H), 3d Battalion(Company I-M), 522d Field Artillery Battalion(Company A-C), 206 Army Band, and 232nd Combat Engineer Company. 

By June 1943, the 442nd RCT arrived at Camp Shelby. The 100th Battalion was just finishing up advanced training in Louisiana. There were some reunions of cousins and old friends, and also at this time some sibling rivalry. The island boys were known as "buddhaheads" (a pidgin English and Japanese term, buta-head, meaning "pig headed"), and the nisei mainlanders were called "kotonks" or "stone head". Kotonk is sometimes described as the sound of an empty head hitting the ground. There were many fights that broke out between the two units during their time together at Camp Shelby, but slowly a mutual respect developed, and soon the 100th Battalion was called and sent overseas while the 442nd started their training. 

In July of 1943, the 100th Infantry Battalion received its colors emblazoned with the motto, "Remember Pearl Harbor." It was time for the men of the 100th Battalion to set off and prove themselves. August 11, 1943, they left Camp Shelby for North Africa. It would be nine long months of heavy fighting before the 442nd would team up with the 100th in Italy. 

Attached to the famed 34th "Red Bull" Division...Landing in Oran, North Africa on September 2, the 100th was originally going to be guarding the supply trains in North Africa. Colonel Farrant L. Turner had other plans and insisted that the 100th be committed to combat. They were then attached to the 34th "Red Bull" Division. The 34th Division was the first US division to enter combat and fought with the British at Kasserine Pass and around Tunis in North Africa. The Commanding General of the 34th Division was Major General Charles W. Ryder. The 100th Battalion took the place of the top-rated 2d Battalion, 133d Infantry Regiment (which was designated as General Dwight D. Eisenhower's headquarters "palace" guards). 

September 19th, 1943, the 34th Division left Oran and headed for Italy. They landed at Salerno, Italy on September 26th, and then the 100th left for their first objective: Monte Marano. On September 28th, 1943, the first casualty of the 100th was taken. 1st Lt. Conrad Tsukayama, then sergeant and squad leader in D Company, was hit by a fragment from a land mine and was slightly wounded in the face. 

On the 29th of September, the 100th led the advance on the drive to Monte Milleto. B Company was on point with the 3d platoon, when the Germans opened fired with machine guns, mortar, and artillery. Sgt. Shigeo "Joe" Takata was hit in the head by a ricocheting machine gun bullet while advancing and spotting a machine gun nest. Dying from his wounds Sgt. Takata pointed out the nest for his platoon and they finally silenced the gun. Later that day in a separate action, Private Tanaka of the 2d platoon was killed to make him the second KIA for the 100th. 

In two days of combat the 100th Battalion gained one hero and started their unwilling start on the "Purple Heart Battalion" legend. They lost 2 men KIA and 7 wounded in action (WIA). The Germans were forced to give up seven miles of real estate, one bridge, two towns, and several road junctions. In the first week of combat (September 28th - October 4th) the 100th suffered 3 KIA, 23 WIA, and 13 injured in accidents. 

Moving north the 100th banged into the 29th Panzer Grenadier Regiment that was defending a road junction near San Angelo d'Alife, on October 17th, 1943. The enemy was entrenched behind minefields and fortified machine-gun nests. Artillery and "screaming meemies"(six barrel rocket launchers) showed shell fragments on the 100th. For two days the 100th and 3d Battalion, 133d Regiment, drove the Germans back and took over the area. It was during this fight that Private Masao Awakuni single-handedly knocked out a tank with his bazooka shot and earned the Distinguished Service Cross. Also during the fight after crossing the Volturno River the platoon led by S/Sgt Ozaki ordered his platoon to fix bayonets and charge toward a hedgerow, over a low stone wall and over the road.