Mikasa is Imperial Japanese Navy pre-dreadnought battleship of her kind . She was built back in 1890s. If you are a fan of Kancolle, Mikasa is depicted as a sexy mature women in a Navy uniform.
She’s named after Mount Mikasa and she served during Russo-Japanese War of 1904?1905 and Battles of the Yellow Sea and Tsushima.
There was an accident thereafter where an explosion happened and sunk Mikasa down which took them 2 years to repair her back.
She joins many more battle after that as a patrol and defense ship. Mikasa is later succeeded by Katori class ship.