Yokosuka Naval Arsenal Officially Abolished

The Yokosuka Naval Arsenal had its origins in the Yokosuka Iron Works, begun by the Tokugawa shogunate in 1865 under the direction of the French engineer Léonce Verny. Taken over by the Meiji government, it was renamed the Yokosuka Shipyard in 1871, the year its No. 1 dry dock was completed, and in 1903 it was reorganised as the Yokosuka Naval Arsenal, one of the four principal naval arsenals of the Imperial Japanese Navy alongside Kure, Sasebo and Maizuru. Ships built there included the battleships Yamashiro and Mutsu and the aircraft carriers Hiryu, Shokaku and Shinano.

During the Pacific War the arsenal built and repaired capital warships and was attacked several times from the air: in the Doolittle Raid on 18 April 1942 the submarine tender Taigei, then being converted into a carrier, was hit, and on 18 July 1945 carrier aircraft struck the naval port and damaged the moored battleship Nagato.

Following Japan's surrender on 15 August 1945, American forces landed at Yokosuka on 30 August, and Japanese Wikipedia records the U.S. Navy as taking over the base on 2 September. The arsenal was officially abolished on 15 October 1945, ending eighty years of history since the iron works; the Yokosuka Naval District itself was abolished on 30 November (per the Japan Center for Asian Historical Records). The facilities passed to the American forces, which set up a Ship Repair Department in April 1947 employing former arsenal workers; this became the U.S. Navy's Ship Repair Facility, and the base developed into U.S. Fleet Activities Yokosuka, home port of the Seventh Fleet and the largest U.S. naval installation in the western Pacific. The arsenal's landmark gantry crane and part of the building ways were returned to Japan in 1959.

The Meiji-era stone dry docks, including No. 1 dock of 1871, are still in use inside the American base. Across the harbour, the Verny Commemorative Museum in Verny Park displays steam hammers imported from the Netherlands for the iron works, designated Important Cultural Properties, and presents the site as the birthplace of modern Japanese shipbuilding.