Kwalajein

colonies until World War I, when they were assigned to Japan in the post-war settlement as the "Eastern Mandates". The islands had become a mystery since the Japanese closed them to the outside world. It was presumed the Japanese had built illegal fortifications throughout the islands, however the precise extent of any such fortifications was unknown. To the Japanese, regarding them as part of the "outer ring" of Japanese territory held prior to 1941, this assault would be the first on what the Japanese regarded as Japanese soil.
After the capture of Makin and Tarawa in the Gilbert Islands, the next step in the United States Navy's campaign in the central Pacific was the Marshall Island chain. These islands had been German