international title Toyota-Denso Cup - World Go Oza.
| Oza | |
|---|---|
| Full name | Oza |
| Started | 1953 |
| Honorary Winners | Masao Kato |
| Sponsors | Nihon Kezai |
| Prize money | ¥14 million $173,000 (as of 2 July 2011) |
| Affiliation | Nihon Ki-in |
Oza (王座 Ōza, Japanese for "Throne") is a title in Go. The association that holds this title is the Japanese Nihon Ki-in.
Recently, the format for the tournament was changed to a best of five. The challenger is decided in a tournament of 16 players, other than the title player. The winner's purse is ¥14 million ($173,000).
| Year | Winner | Score | Runner-up |
|---|---|---|---|
| 1953 | Utaro Hashimoto | 1-0 | Nobuaki Maeda |
| 1954 | Kaku Takagawa | 2-1 | Hidehiro Miyashita |
| 1955 | Utaro Hashimoto | 2-1 | Toshihiro Shimamura |
| 1956 | Utaro Hashimoto | 2-0 | Eio Sakata |
| 1957 | Toshihiro Shimamura | 2-0 | Dogen Handa |
| 1958 | Hosai Fujisawa | 2-0 | Dogen Handa |
| 1959 | Shoji Hashimoto | 2-0 | Toshiro Yamabe |
| 1960 | Dogen Handa | 2-0 | Hidehiro Miyashita |
| 1961 | Eio Sakata | 2-1 | Kaku Takagawa |
| 1962 | Hidehiro Miyashita | 2-0 | Katsuji Kada |
| 1963 | Eio Sakata | 2-0 | Hosai Fujisawa |
| 1964 | Eio Sakata | 2-0 | Takeo Kajiwara |
| 1965 | Dogen Handa | 2-0 | Ichigen Okubo |
| 1966 | Eio Sakata | 2-1 | Rin Kaiho |
| 1967 | Hideyuki Fujisawa | 2-0 | Shoji Hashimoto |
| 1968 | Hideyuki Fujisawa | 2-0 | Eio Sakata |
| 1969 | Hideyuki Fujisawa | 2-0 | Hideo Otake |
| 1970 | Eio Sakata | 2-0 | Hideyuki Fujisawa |
| 1971 | Eio Sakata | 2-0 | Shoji Hashimoto |
| 1972 | Eio Sakata | 2-1 | Utaro Hashimoto |
| 1973 | Rin Kaiho | 2-1 | Eio Sakata |
| 1974 | Yoshio Ishida | 2-1 | Rin Kaiho |
| 1975 | Hideo Otake | 2-0 | Yoshio Ishida |
| 1976 | Cho Chikun | 2-1 | Hideo Otake |
| 1977 | Norio Kudo | 2-0 | Cho Chikun |
| 1978 | Yoshio Ishida | 2-1 | Norio Kudo |
| 1979 | Masao Kato | 2-0 | Yoshio Ishida |
| 1980 | Masao Kato | 2-0 | Yoshio Ishida |
| 1981 | Shoji Hashimoto | 2-1 | Masao Kato |
| 1982 | Masao Kato | 2-0 | Shoji Hashimoto |
| 1983 | Masao Kato | 2-0 | Hideo Otake |
| 1984 | Masao Kato | 3-0 | Hiroshi Yamashiro |
| 1985 | Masao Kato | 3-0 | Koichi Kobayashi |
| 1986 | Masao Kato | 3-1 | Rin Kaiho |
| 1987 | Masao Kato | 3-1 | Cho Chikun |
| 1988 | Masao Kato | 3-0 | Masaki Takemiya |
| 1989 | Masao Kato | 3-1 | Yasumasa Hane |
| 1990 | Yasumasa Hane | 3-2 | Masao Kato |
| 1991 | Hideyuki Fujisawa | 3-1 | Yasumasa Hane |
| 1992 | Hideyuki Fujisawa | 3-2 | Koichi Kobayashi |
| 1993 | Masao Kato | 3-0 | Hideyuki Fujisawa |
| 1994 | Cho Chikun | 3-2 | Masao Kato |
| 1995 | O Rissei | 3-0 | Cho Chikun |
| 1996 | Ryu Shikun | 3-0 | O Rissei |
| 1997 | Kimio Yamada | 3-1 | Ryu Shikun |
| 1998 | O Rissei | 3-0 | Kimio Yamada |
| 1999 | O Rissei | 3-1 | Cho Chikun |
| 2000 | O Rissei | 3-1 | Cho Chikun |
| 2001 | Cho Chikun | 3-0 | O Rissei |
| 2002 | O Meien | 3-2 | Cho Chikun |
| 2003 | Cho U | 3-1 | O Meien |
| 2004 | Cho U | 3-1 | Keigo Yamashita |
| 2005 | Cho U | 3-0 | Keigo Yamashita |
| 2006 | Keigo Yamashita | 3-1 | Cho U |
| 2007 | Keigo Yamashita | 3-1 | Toshiya Imamura |
| 2008 | Cho U | 3-1 | Keigo Yamashita |
| 2009 | Cho U | 3-0 | Kimio Yamada |
| 2010 | Cho U | 3-0 | Kimio Yamada |
| 2011 | Cho U | 3-0 | Hane Naoki |
| 2012 | Yuta Iyama | 3-0 | Cho U |
| 2013 | Yuta Iyama | 3-1 | Cho U |
| 2014 | Daisuke Murakawa | 3-2 | Yuta Iyama |
| 2015 | Yuta Iyama | 3-0 | Daisuke Murakawa |