Oza tournament was established in 1953, but status of title one it got only in 1983. All professionals and 4 women professionals pfrticipate in Oza tournament. The 16 best players by results of preliminary rounds in play-off games define the challenger. TIme limit is 5 hours for every player.
Oza title match is playing from September to October. It is necessary to win 3 title games to get Oza title. Every title game plays during one day. Time limit is 5 hours for every players.
By materials of japanese resources
Andrei Kasperovich, 2006