From 1905 to 1906, the empires of Russia and Japan fought over the continental territories of Manchuria and Korea in the Russo-Japanese War. While Russia led the powerful and massive Baltic Fleet, they were defeated in the Battle of Tsushima Strait by the Combined Fleet of Japan, who only lost a few of its ships. It was a significant victory that was encouraging to people from other Asian nations (including a young Pandit Jawaharlal Nehru), and indirectly led to the October Revolution.

The Combined Fleet was led by Vice Admiral Tōgō Heihachirō, the Nelson of the East, whose flagship was Mikasa. The ship was named after Mount Mikasa in Nara (now called Mount Wakakusa), and was built by Vickers in 1902. Today the vessel can be found at the edge of the seaside Mikasa Park in Yokosuka, near the U.S. Navy base. Mikasa is the last remaining battleship of pre-dreadnought class, and has been a museum ship since 1926, three years after she was severely damaged in the Great Kantō earthquake.

After the Second World War, Mikasa was consigned to a private company who sold off the ship's cannons and masts, building a dance hall and an aquarium instead. Her newfound popularity didn't last long, however, and soon she was all but abandoned and left to rust away.

In 1955, the British businessman John Rubin was shocked and saddened by the state of Mikasa and wrote a letter to the Japan Times about it. The published article caused a restoration campaign, and with the support of the Japanese public and U.S. admiral Chester W. Nimitz, Mikasa reclaimed her former glory.

Today, the museum exhibits include various cannons, helms, boats, torpedoes, mannequins displaying naval actions, an educational video room, and even a virtual reality experience. Another interesting exhibit is a lantern made out of damaged ship parts, once a gift to the first prime minister of Japan, Itō Hirobumi, which can be found on the main deck. There are several artillery shells displayed outside Mikasa, right beside the ship.