The world’s second largest island, New Guinea represented an important island for both the enemy and Allied forces. The Japanese could use the island to disrupt Allied communication, and could build a base that could dominate other local islands. The Allied forces hoped to disrupt the Japanese before they could reach Australia.

Starting from the northern end of the island, 14,000 Japanese troops marched toward Port Moresby on the Australian side. The campaign cost many lives but was the first land defeat of Japanese forces. Many Nisei participated in this island battle. This victory allowed the Allies to continue pushing the Japanese off the western end of the island.

On April 18, 1943, U.S. Navy radio operators in Alaska, Hawaii, and Port Moresby intercepted a message indicating the specific time the infamous Admiral Yamamoto would arrive to visit troops on Bougainville (Yamamoto had planned the Pearl Harbor attack). Based on these broadcasts, Yamamoto was successfully shot down.

Some accounts of this important incident conceal the Nisei linguists’ role:

“He (Yamamoto) was shot down over Bougainville while on a tour of inspection. ‘Magic’ was responsible for the successful intercept of his aircraft. His death was a grievous blow to the Japanese." (Dated Atlas of WWII, p.145).

The Japanese based their best pilots and planes on Rabaul, New Britain. Instead of a straightforward attack, Allied Forces captured islands surrounding Rabaul. They cut off its supply sources while making frequent air strikes against the base.

In coordination with campaigns on Bougainville and western New Guinea, Nisei MIS linguists landed with Allied troops on Los Negros in the Admiralty Islands and successfully surrounded Rabaul. In December 1943, Nisei MIS linguists participated in the capture of the island.

The Japanese planned an all-out counter attack in the Central Pacific called "Operation Z.” Vice Admiral Fukudome, Chief of Staff, carried the plan in a waterproof container while flying from the southern Philippines. His plane crashed in a storm. Filipino soldiers captured the document and sent it to U.S. forces. Top Nisei linguists translated the documents quickly and gave Allied Forces time to prepare for the attack.

The battle, dubbed “The Great Marianas Turkey Shoot”, broke Japanese naval air power. Military historians termed it“the most significant enemy document seized during the war.”