Designed by Yuzuru Hiraga the tosa class, composed by IJN Tosa and IJN Kaga where supposed to be the successor of the Nagato class battleships, armed with 10 16.1-inch (409mm) guns and capable of 26,5 knots they would have been among the most powerful capital ships of their time (US South Dakotas has 12x16-inch but where 3,5 knots slower).
Construction was however halted in 1922 after Japan signed the Washington Naval Treaty, Tosa, only 5 monts before completion was converted into a gunnery test ship and eventually scuttled in 1925, Kaga was converted into a Carrier and was sunk in the famous Battle of Midway.
IJN Tosa as she looked as a target ship after all works where canceled because of the Washington treaty:
and how could she have looked if completed in 1923.