The First Naval Port in Japan is located in Yokosuka Port on the east coast of the entrance to Tokyo Bay on Honshu Island, Japan. It is connected to Yokohama City to the north and the east coast of Yokosuka City to the south. The port has berthing facilities, ship repair capabilities, oil and It has unique conditions in terms of ammunition storage equipment and rest facilities for soldiers, and has all the conditions required for a naval base. It is known as the first military port in the East. The water area in the port is open (the waterline area is more than 30 square kilometers), the water depth is slow (the water depth is 7 to 30 meters, the tidal direction is basically north to south to east, and the speed is about 1 knot). There is no need for dredging, and the water area in the port is open. , with a concealed terrain and strong berthing capabilities, it can berth more than 300 ships of various types including aircraft carriers at the same time. It is one of the few natural harbors in Japan. The entire port area is shaped like a human hand, with the "thumb" directly touching Yokohama City, which is the fourth district; on the root of the "index finger" divided by Usai Island, there are two breakwaters (East Breakwater and Northeast Breakwater), and the Northeast Breakwater will be " The palm is divided into two, the outer half is the outer harbor, which is also the quarantine anchorage; the inner half is the third area of ??the inner harbor. The high tide of the inner harbor is north-northwest, with a speed of 0.6 to 0.7 knots; The ebb current is southeast and south-southeast, with a speed of 1 to 1.2 knots. The high tide in the outer harbor is northward, with a speed of 1.1 knots. The ebb tide is southerly, with a speed of 1 knot. The main navigation signs after entering the port area are. , the light pile at the end of the breakwater and the corresponding signal tower, as well as isolated Japanese landmarks such as Sarushima
It is precisely because of this unique geographical location that the US military landed here after the end of World War II and was stationed in Yokosuka-mae. On the site of the Navy Yard. In 1947, the U.S. military successively established a ship repair department, a supply station, and a port administration department, forming a de facto U.S. naval base. After the signing of the San Francisco Peace Treaty, Japan transferred Yokosuka in 1952 according to the Japan-U.S. Security Treaty. The base was officially provided to the U.S. military. In this way, the Yokosuka base became the joint location of the Japan Maritime Self-Defense Fleet Command and the U.S. Naval Command in Japan (the 7th Fleet Command). Military restricted area (no general ships are allowed to enter), it is the largest and most comprehensive naval base of the United States in the Far East. It is evaluated as "one of the largest and best-conditioned bases among the overseas naval bases of the United States", covering an area of ??approximately It covers an area of ??2.3 million square meters and was formerly the naval base of the old Japanese Empire. It also includes the Yokosuka capital of the old navy, the naval factory, the Marine Corps, schools and other buildings. The base was formerly founded by the Edo shogunate in 1865. A shipyard, "Yokosuka Iron Works", was later placed under the jurisdiction of the Navy Ministry by the then Meiji government in 1872. In 1903, it was renamed "Yokosuka Naval Factory", and the prototype of a naval base was formed with the end of the 19th century. During the Russo-Japanese War and the First World War in 1904-1905, the plant's shipbuilding capabilities were greatly improved, and it had the ability to build cruisers, battleships and other main ships of the time until World War II. During the World War, the total number of employees reached more than 40,000. Not only did its ship repair capabilities reach the first-class level at that time, but it also became the headquarters of the old Imperial Japanese Navy (the base currently serves as the underground headquarters of the 7th Fleet, which is the former Imperial Japanese Navy). Navy War Room). When Japan surrendered in 1945, the United States landed in Yokosuka on August 26 and 8 of the same year and took over the base. In 1947, it successively established a ship repair department, a supply station, and a port department. The U.S. military began to intervene in Yokosuka. Subsequently, the U.S. military requested Japan to provide bases for them due to their needs in the Far East, so the Japan-U.S. Security Treaty clearly stated that the Japanese government should provide bases for U.S. troops stationed in Japan. In order to fulfill the provisions of the security treaty, Japan officially provided the Yokosuka Base to the US military in July 1952.
After years of construction, the Yokosuka Base is not only the largest comprehensive operational base of the Japanese Navy and the maritime gateway to Tokyo. , and it is also the largest comprehensive naval base and the largest ship maintenance base of the US Navy in the Western Pacific.
Since October 1973, in order to strengthen the U.S. Navy's combat capabilities in the waters surrounding Japan, the U.S. 7th Fleet's "Midway" aircraft carrier group has been stationed at the Yokosuka base, making it the U.S. military's only aircraft carrier homeport overseas. In June 1984, after the United States announced the deployment of Tomahawk cruise missiles, the 5th Fleet with the Middle East as its defense area also stationed its submarine force in Yokosuka. In addition, near the Yokosuka base is the largest U.S. naval aviation facility in the Western Pacific, home to the U.S. 5th aircraft carrier fighter wing. Yokosuka is therefore nicknamed the base of the "Two Straw Shoes" (5th and 7th Fleets). At present, the US military has 18 piers of various types at the base, with a total length of 2,516 meters, divided into 19 berths (berths 14 to 17 are in the dock at No. 6). Among them, the small harbor area has been the main dock since 1966. There are no radioactive monitoring posts at the berths where nuclear submarines often dock. In the base, there are the headquarters of the U.S. Navy in Japan, the Yokosuka Fleet Base Headquarters, the 7th Submarine Group Headquarters, a ship repair department, a supply depot, an engineering center, a regional medical center and other institutions. The troops stationed there include: The 10 combat ships of the 7th Fleet flagship "Blue Ridge" command ship, the U.S. Navy communications force stationed in Japan, the Marine Corps (Guard), etc. The "Blue Ridge" has been stationed here since October 6, 1978. Among the 10 combat ships, one was the aircraft carrier "Midway". It has been using this as its home port since March 5, 1973 and has now been retired. It can be seen that Yokosuka is also the only aircraft carrier home port among the overseas ports of the US Navy (there are two piers with a length of 255 meters and 280 meters respectively for aircraft carriers to dock). This is because in addition to good berthing conditions, Yokosuka has Atsugi Airport nearby; on the other hand, it has outstanding ship repair capabilities, which not only increases the sailing rate of the "Midway" since it has become its home port It has been ranked among the best since then, and has provided guarantee for its repeated extension of service period.