20 Steps in Planning for the Invasion of Japan in 1945

Admiral Nimitz (with pointer) was wary of Japan’s kamikaze weapons and supported the idea of blockade and bombardment rather than invasion. National Archives

2. The Navy initially opposed the invasion before committing what would have been the largest invasion fleet in history

By the late summer of 1945, in what turned out to be the last two weeks of the war, battleships and cruisers were bombarding the home islands of Japan. The bombardments were primarily by ships of the US Navy, supported by the Royal Navy and the Royal New Zealand Navy, and the damage inflicted to Japanese industry and infrastructure was extensive. When the Japanese did not strike at the bombarding ships the Allies committed destroyers to the bombardment operations. Meanwhile shipping to and from Japan, as well as between the islands of the nation, was brought to a near standstill. The bombardments effectiveness, as well as the lack of Allied casualties, led the Navy to support a strategy of blockade, rather than invasion.

MacArthur argued for invasion, believing that a blockade could be a lengthy process, and would have a deleterious effect on American morale, especially with some American troops coming home from the European theater. Once the decision was made that the invasion would go forward, the Navy committed a force of 24 battleships and 42 aircraft carriers, supported by four hundred destroyers and destroyer escorts, itself a testament to the massive American industrial expansion in World War II. By comparison the Japanese fleet had 5 battleships, all damaged and lacking the fuel to leave their moorings, and five aircraft carriers, in the same relatively helpless position.