オレンジ計画
After World War I, the Versailles Treaty gave Japan a mandate over former German colonies in the western Pacific; specifically, the Mariana, Marshall, and the Caroline Islands. If these islands were fortified, Japan could, in principle, deny the U.S. access to its interests in the western Pacific. Therefore, in 1921, Major Earl Hancock Ellis of the U.S. Marine Corps drafted "Plan 712, Advanced Base Operations in Micronesia," a plan for war against Japan which updated War Plan Orange by incorporating modern military technology (submarines, aircraft, etc.) and which again included an island-hopping strategy. Shortly afterward, a British reporter on naval affairs, Hector Charles Bywater, publicized the prospect of a Japanese-American war in his books "Seapower in the Pacific" (1921) and "The Great Pacific War" (1925), which detailed an island-hopping strategy. The books were read not only by Americans but by senior officers of the Japanese Imperial Navy, who used "island-hopping" in their successful southeast Asia offensives in 1941 and 1942.