The were naval bases, similar to the , with docking, fueling and resupply facilities, but typically lacked a shipyard or training school. They tended to be established by strategic waterways or major port cities for defensive purposes. In concept, the Guard District was similar to the
United States Navy Sea Frontiers concept. the Guard District maintained a
garrison force of ships and
Naval Land Forces which reported directly to the Guard District commander, and hosted detachments of the
numbered fleets on a temporary assignment basis. The port of Chinkai in Korea was an area with long associations with Japan, having been the location of a Japanese fish
trading settlement in the 15th and 16th centuries. More recently, it was the location where Admiral
Tōgō Heihachirō assembled his
Combined Fleet while waiting for the arrival of the
Russian Baltic Fleet prior to the
Battle of Tsushima in the
Russo-Japanese War. After the
annexation of Korea by the
Empire of Japan in 1910, the Imperial Japanese Navy built extensive port facilities, transforming the small town into a major naval port. The port was upgraded to a Guard District on April 1, 1916. After the Russo-Japanese War the port was briefly considered a backwater assignment. However, the start of the Second Sino-Japanese War in 1937 re-established Jinhae as Japanese Empire's strategic port on mainland Asia. At the start of the Pacific War, Chinkai was home to destroyers Minekaze, Asagao, Fuyo, and Karukaya; Minesweeper Divisions 48 and 49; as well as Chinkai Naval Air Group. On the
surrender of Japan, Chinkai was occupied by Destroyer Squadron 64 from the
United States Navy led by the
USS Harry E. Hubbard (DD-748). It was repaired and continued to be used as a naval base during the
Korean War. After the independence of Korea in 1945, the naval base was turned over to the
Republic of Korea Navy, and remains a major naval base to this date. A subsidiary naval base reporting to the Chinkai Guard District existed at Rashin (present day
Rason,
North Korea), , on the east coast of Korea near the border with the
Soviet Union. ==Order of battle at time of the
attack on Pearl Harbor==