The Okan title is a 1-game match between the winner of a 12-player knockout tournament and the previous title holder. It is open only to players in the Nagoya branch of the Nihon Ki-in. It is held every year (but up to the 15th Okan, every year-and-a-half).
Komi was 4.5 up to 1974, 5.5 in 1975-2002, and 6.5 from 2003.
For the early years, no game records are available.
| # | year | winner |
|---|---|---|
| 1 | 1950 | Sakai Toshio |
| 2 | 1952 | Sakai Toshio |
| 3 | 1954 | Sakai Toshio |
| 4 | 1955 | Sakai Toshio |
| # | year | winner | loser |
|---|---|---|---|
| 5 | 1957 | Shimamura Toshihiro | Sakai Toshio |
| 6 | 1959 | Shimamura Toshihiro | Isogawa Masao |
| 7 | 1960 | Shimamura Toshihiro | Isogawa Masao |
| 8 | 1962 | Shimamura Toshihiro | Isogawa Masao |
| 9 | 1964 | Shimamura Toshihiro | Isogawa masao |
| 10 | 1965 | Shimamura Toshihiro | Iwata Tatsuaki |
| 11 | 1967 | Iwata Tatsuaki | Shimamura Toshihiro |
| 12 | 1969 | Iwata Tatsuaki | Shimamura Toshihiro |
| 13 | 1970 | Iwata Tatsuaki | Tsuchida Masamitsu |
| 14 | 1972 | Hane Yasumasa | Iwata Tatsuaki |
| 15 | 1974 | Shimamura Toshihiro | Hane Yasumasa |
| 16 | 1975 | Shimamura Toshihiro | Hane Yasumasa |
| 17 | 1976 | Iwata Tatsuaki | Shimamura Toshihiro |
| 18 | 1977 | Yamashiro Hiroshi | Iwata Tatsuaki |
| 19 | 1978 | Hane Yasumasa | Yamashiro Hiroshi |
| 20 | 1979 | Iwata Tatsuaki | Hane Yasumasa |
Game records for the title games, starting at 1980.
| # | date | winner | loser | #mv | result | sgf |
|---|---|---|---|---|---|---|
| 21 | 1980-10-23 | Iwata Tatsuaki | Baba Shigeru | 101 | B+R | sgf |
| 22 | 1981-11-05 | Yamashiro Hiroshi | Iwata Tatsuaki | 234 | B+2.5 | sgf |
| 23 | 1982-10-21 | Yamashiro Hiroshi | Hane Yasumasa | 205 | B+R | sgf |
| 24 | 1983-11-24 | Hane Yasumasa | Yamashiro Hiroshi | 172 | W+R | sgf |
| 25 | 1984-11-22 | Yamashiro Hiroshi | Hane Yasumasa | 168 | W+R | sgf |
| 26 | 1985-11-21 | Yamashiro Hiroshi | Iwata Tatsuaki | 195 | B+R | sgf |
| 27 | 1986-11-20 | Yamashiro Hiroshi | Hane Yasumasa | 205 | B+R | sgf |
| 28 | 1987-11-12 | Yamashiro Hiroshi | Tsuchida Masamitsu | 263 | B+4.5 | sgf |
| 29 | 1988-12-08 | Ogata Masaki | Yamashiro Hiroshi | 180 | W+R | sgf |
| 30 | 1989-11-09 | Ogata Masaki | Iwata Tatsuaki | 262 | B+1.5 | sgf |
| 31 | 1990-11-02 | Ogata Masaki | Hane Yasumasa | 172 | W+R | sgf |
| 32 | 1991-11-07 | Ogata Masaki | Hane Yasumasa | 232 | W+R | sgf |
| 33 | 1992-11-05 | Hane Yasumasa | Ogata Masaki | 190 | W+R | sgf |
| 34 | 1993-11-10 | Yamashiro Hiroshi | Hane Yasumasa | 242 | B+0.5 | sgf |
| 35 | 1994-11-10 | Yamashiro Hiroshi | Ogata Masaki | 246 | W+1.5 | sgf |
| 36 | 1995-11-16 | Yamashiro Hiroshi | Hane Yasumasa | 219 | B+R | sgf |
| 37 | 1996-11-14 | Yamashiro Hiroshi | Hikosaka Naoto | 206 | W+0.5 | sgf |
| 38 | 1997-11-20 | Nakano Hironari | Yamashiro Hiroshi | 253 | B+3.5 | sgf |
| 39 | 1998-11-18 | Nakano Hironari | Yamashiro Hiroshi | 176 | W+R | sgf |
| 40 | 1999-10-19 | Hane Naoki | Nakano Hironari | 144 | W+R | sgf |
| 41 | 2000-11-20 | Yamashiro Hiroshi | Hane Naoki | 213 | B+R | sgf |
| 42 | 2001-11-21 | Yamashiro Hiroshi | Matsuoka Hideki | 212 | W+7.5 | sgf |
| 43 | 2002-11-14 | Hane Naoki | Yamashiro Hiroshi | 220 | W+2.5 | sgf |
| 44 | 2003-11-10 | Hane Naoki | Hikosaka Naoto | 286 | W+3.5 | sgf |
| 45 | 2004-11-17 | Hane Naoki | Yamashiro Hiroshi | 175 | B+R | sgf |
| 46 | 2005-11-28 | Yamashiro Hiroshi | Hane Naoki | 283 | B+R | sgf |
| 47 | 2006-11-27 | Matsuoka Hideki | Yamashiro Hiroshi | 183 | B+R | sgf |
| 48 | 2007-11-28 | Hane Naoki | Matsuoka Hideki | 139 | B+R | sgf |
| 49 | 2008-11-17 | Hane Naoki | Yamashiro Hiroshi | 192 | W+R | sgf |
| 50 | 2009-11-26 | Hane Naoki | Yamashiro Hiroshi | 176 | W+R | sgf |
| 51 | 2010-11-25 | Yamashiro Hiroshi | Hane Naoki | 242 | W+4.5 | sgf |
| 52 | 2011-11-16 | Hane Naoki | Yamashiro Hiroshi | 299 | B+5.5 | sgf |
| 53 | 2012-11-27 | Hane Naoki | Nakano Hironari | 265 | W+3.5 | sgf |
| 54 | 2013-11-29 | Hane Naoki | Nakano Hironari | 237 | B+R | sgf |
| 55 | 2014-11-29 | Hane Naoki | Yamashiro Hiroshi | 198 | W+R | sgf |
| 56 | 2015-12-04 | Hane Naoki | Ogata Masaki | 150 | W+R | sgf |