Masao Kato Honorary Oza (?? ??, Kato Masao, March 15, 1947 – December 30, 2004), also known as Kato Kensei (???? Kato Kensei), was a Japanese professional go player.
A late bloomer, Kato won 46 titles, including the Oza eight times in a row.
He also became the second player to reach 1,200 career wins, behind Rin Kaiho.Kato is the author of The Chinese Opening: The Sure-Win Strategy (published in English by Kiseido Publishing Company) and Kato's Attack and Kill (published by Ishi Press).