Mikasa is a pre-dreadnought battleship built for the Imperial Japanese Navy (IJN) in the late 1890s, and was the only ship of her class. Named after Mount Mikasa in Nara, Japan, the ship served as the flagship of Admiral Tōgō Heihachirō throughout the Russo-Japanese War of 1904–1905, including the Battle of Port Arthur on the second day of the war and the Battles of the Yellow Sea and Tsushima. Days after the end of the Russo-Japanese War, Mikasa's magazine accidentally exploded and sank the ship. She was salvaged and her repairs took over two years to complete. Afterwards, the ship served as a coast-defence ship during World War I and supported Japanese forces during the Siberian Intervention in the Russian Civil War.
After 1922, Mikasa was decommissioned in accordance with the Washington Naval Treaty and preserved as a museum ship at Yokosuka. She was badly neglected during the post-World War II Occupation of Japan and required extensive refurbishing in the late 1950s. She is now fully restored as a museum ship and can be visited at Mikasa Park in Yokosuka.
Mikasa is the last remaining example of a pre-dreadnought battleship anywhere in the world.
The ship was decommissioned on 23 September 1923 following the Washington Naval Treaty of 1922 and scheduled for destruction. However, at the request of the Japanese government, each of the signatory countries to the treaty agreed that Mikasa could be preserved as a memorial ship with her hull encased in concrete. On 12 November 1926, Mikasa was opened for display in Yokosuka in the presence of the Crown Prince, Prince Hirohito and Tōgō. Following the surrender of Japan in 1945, the ship deteriorated under control of the occupation forces, but was restored after another campaign led by the Japan Times and Fleet Admiral Chester W. Nimitz that allowed the ship to reopen in 1961. On 5 August 2009, Mikasa was repainted by sailors from USS Nimitz.