Leapfrogging (strategy)

Leapfrogging, also known as island hopping, was a military strategy employed by the Allies in the Pacific War against the Empire of Japan during World War II.

The key idea is to bypass heavily fortified enemy islands instead of trying to capture every island in sequence en route to a final target. The reasoning is that those islands can simply be cut off from their supply chains (leading to their eventual capitulation) rather than needing to be overwhelmed by superior force, thus speeding up progress and reducing losses of troops and materiel.

Background

By the late 19th century, the U.S. had several interests in the western Pacific to defend; namely, access to the Chinese market, and its colonies – the Philippines and Guam – which the U.S. had gained as a result of the Spanish–American War (1898). After Japan's victories in the Sino-Japanese War (1894–95) and the Russo-Japanese War of 1904, the U.S. began to regard Japan as a potential threat to its interests in the western Pacific. This antagonism was intensified by Japan's objections to an attempt to annex Hawaii to the U.S. (1893) and by Japan's objections to discrimination against Japanese immigrants both in Hawaii (1897) – on this occasion, Japan sent the cruiser ''Naniwa'' to Honolulu, Hawaii – and in California (1906, 1913). As a result, the U.S. Navy began to draft, as early as 1897, war plans against Japan, which were eventually code-named " War Plan Orange". The war plan of 1911, which was drafted under Rear Admiral Raymond P. Rodgers, included an island-hopping strategy for approaching Japan.

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.

Rationale and use

This strategy was possible in part because the Allies used submarine and air attacks to blockade and isolate Japanese bases, weakening their garrisons and reducing the Japanese ability to resupply and reinforce them. Thus troops on islands which had been bypassed, such as the major base at Rabaul, were useless to the Japanese war effort and left to "wither on the vine". General Douglas MacArthur greatly supported this strategy in his effort to regain the Philippines from Japanese occupation. This strategy began to be implemented in late 1943 in Operation Cartwheel. While MacArthur claimed to have invented the strategy, it initially came out of the Navy. While this strategy pre-dated World War II by many decades, MacArthur was the first Allied theater commander to practice this during the Allied offensive in the Pacific Theater. MacArthur's Operation Cartwheel, Operation Reckless and Operation Persecution were the first successful Allied practices of leapfrogging in terms of landing on lightly guarded beaches and very low casualties but cutting off Japanese troops hundreds of miles away from their supply routes. MacArthur said his version of leapfrogging was different from what he called island hopping, which was the style favored by the Central Pacific Area commanded by Admiral Chester Nimitz that favored direct assaults on heavily defended beaches and islands leading to massive casualties for such small parcels of land like at Tarawa