Imperial Japanese Navy

This theme covers the sites left by the Imperial Japanese Navy (IJN), the naval arm of the Empire of Japan, in the home islands and overseas territories. The Navy was directed from the Navy Ministry and Naval General Staff in Tokyo and divided the coast into naval districts under four chinjufu at Yokosuka, Kure, Sasebo and Maizuru. Each had an arsenal, barracks, hospital, and fuel and ammunition depots, and around each grew a naval-port city. There were also guard districts such as Ōminato, naval air groups and communications units across the country, and schools such as the Naval Academy at Etajima.

After its victories in the Sino-Japanese and Russo-Japanese Wars the Navy ranked with those of Britain and the United States. The Washington (1922) and London (1930) treaties capped its tonnage, and it turned to ship quality, torpedo tactics and air power; in the treaty-free years of the late 1930s it built the Yamato-class battleships alongside carrier task forces and land-based attack units. By 1941, it operated one of the largest and most technologically advanced fleets in the world, including aircraft carriers, battleships, submarines, and naval aviation. After Midway and the attrition of the Solomons it could not match American replacement of ships, aircraft and trained men; the battles of the Philippine Sea and Leyte Gulf in 1944 ended the Combined Fleet as an organised force, and in the final phase the Navy turned to special attack by air, surface and underwater craft. The Navy Ministry was abolished on November 30, 1945.

The Navy illuminates several structural problems of wartime Japan: the Army and Navy each answered directly to the Emperor and competed over strategy and resources; the huge shipbuilding and aircraft programmes drove the mobilisation of steel, fuel and labour; and the naval-port cities rose with the Navy, were destroyed by air raids, and became after the war shipbuilding towns, U.S. bases and bases of the Maritime Self-Defense Force.

Under this theme visitors will find naval district headquarters, red-brick warehouses, docks and cranes; air group headquarters, shelters and seaplane ramps; radio towers; fuel depots and magazines; and training bases for special attack weapons such as the Kaiten and Shin'yō. Its major bases, shipyards, and command centers were spread across Japan, from Yokosuka and Kure to Sasebo and Maizuru, whose naval heritage was recognised as the Japan Heritage "Chinjufu" in 2016. Some sites lie inside active Self-Defense Force or U.S. bases, so access conditions should be checked.