The Japanese viewed the native Chamorro people as inferior and untrustworthy, and over the course of the occupation subjected them to forced labor and cultural repression.
[1] By early 1944, American forces had made westward gains across the Pacific Ocean, prompting the Japanese to reinforce the island and expand its defenses.
[1] In late June, American forces succeeded in the Battle of Saipan in the nearby Mariana Islands.
On July 4, Colonel Okabe Eichi issued an order calling for the Chamorro populations of the three largest villages to be moved to Mangilao.
Nearby natural food sources were quickly depleted, and the Japanese banned any use of fire so as to not alert American forces.