Along with the rapid progress of military technology、the competition to build new battleships intensified. Based on such naval competition in the world in 1922, the Washington Naval Treaty was concluded, which imposed limits on the number of capital ships possessed by Japan, the United States, Great Britain, France, and Italy.
Japan that signed the Washington Naval Treaty, decided to remove the old MIKASA from its warship registry and to decommission it. However both at home and abroad there was a growing voice that MIKASA contributed greatly to the victory of the Japanese-Russo War and protected the independence of Japan, should be preserved forever as a symbol of national pride. Because of this background and after obtaining the consent of the signatories to the Treaty, Japan decided to preserve MIKASA as a memorial ship.
MIKASA was flooded and stranded outside Yokosuka Port due to a bottom crack caused by the Great Kanto Earthquake. However, in October 1925, taking advantage of the high tide, MIKASA was lifted off the rock by a tugboat and pulled into the present position where the rock was excavated and settled down pointing its bow to the Imperial Palace. On 12 November 1926, a grand preservation ceremony was held in the presence of His Imperial Highness Prince Regent (later Emperor Showa).