Kwajalein Atoll was the administrative center of the Japanese-held Marshall Islands. The atoll was seventy-three miles long, with eighteen islands clustered together. During the Battle of Midway radio stations on Kwajalein listened to traffic between Hawaii and Midway.
When the Americans moved through the Marshalls in early 1944, Kwajalein was a primary target. With Kwajalein in Japanese hands for decades, it was assumed that there would be casualties as heavy as Tarawa. A sustained air campaign from the Gilberts and from aircraft carriers pounded Kwajalein for days prior to the landings on January 31, 1944.
Resistance was light as the United States Army and Marines moved through the atoll. On the island of Kwajalein itself, 10,000 Japanese soldiers waited for the United States Army’s 7th Division. By February 3, 8,400 Japanese were dead, mostly by suicide. 500 Americans died.
The last year of the war saw escalating dead and wounded on both sides. Half of all the casualties in the Pacific War was during the last year of the war. Kwajalein showed the Americans that heavy pre-invasion bombardment was a necessary component to amphibious landings. The old, slow battleships that America started the war with became floating gun platforms to support the invasions, and escort carriers brought aircraft to fly ground support missions.
At Kwajalein, these new tactics were tried out. The result was huge Japanese casualties. This would be the pattern for the rest of the war.