Winning Shusaku Number
Whereas a Shusaku Number is calculated by considering games played, a winning shusaku number is calculated using wins only. So:
A defeated B, B defeated C, C defeated D, ...., H defeated I, I defeated Shusaku.
To keep the winning shusaku number pure, you should only count wins that happened sequentially. So:
A defeated B after B defeated C after C defeated D, etc
So anyone who has defeated Shusaku has a winning Shusaku number of 1, anyone who has defeated a player that defeated Shusaku has a winning Shusaku number of 2, etc.
Thomas Debarre: I calculated my (winning) Shusaku number through won, even and official games, only. It was a quite difficult research, but I found the most resourceful player who beat Shusaku was Murase Shuho (source: GoBase). I calculated mine, which is astonishingly low (9) compared to my normal Shusaku number of 6.
0. Honinbo Shusaku
1. Murase Shuho(JP, B) vs. Shusaku Honinbo(JP, W) 1861-12-08 ; Black won by resignation
2. Honinbo Shuei (JP, B) vs. Murase Shuho (JP, W) 1885-03-05 ; Black won by 3 points
3. Honinbo Shusai (JP, B) vs. Honinbo Shuei (JP, W) 1903-08-16 ; Black won by resignation
4. Kitani Minoru (JP, B) vs. Honinbo Shusai (JP, W) 1938-06-26 ; Black won by 5 points
5. Otake Hideo (JP, B) vs. Kitani Minoru (JP, W) 1960-10 ; Black won by 16 points
6. Rui Naiwei (CN, W) vs. Otake Hideo (JP, B) 1992-11-25 ; White won by resignation
7. Guo Juan (CN, B) vs. Rui Naiwei (CHN, W) 1985-05-02 ; Black won by resignation
8. Geert Groenen? (NL, W) vs. Guo Juan (CHN, B) 2003-05-31 ; White won
9. Thomas Debarre (FR, W) vs. Groenen Geert (NL, B) 2006-05-27 ; White won by 1,5 points
Note: some players are known as in different names (i.e. Murase Shuho is also known as Honinbo Shuho or Murase Yakichi, Honinbo Shuei as Hayashi Shuei, Shusai with Honinbo or Meijin or as Tamura Hoju...)
The above example is not completely pure. The victory by Guo Juan over Rui Naiwei happened before Rui Naiwei defeated Otake Hideo.
Here are some other paths into Europe:
- Catalin Taranu (7) - Yamashiro Hiroshi (6) - Otake Hideo (5) - Kitani (4) - Shusai (3) - Shuei (2) - Shuho (1) - Shusaku (0)
- Alexandre Dinerchtein (7) - O Rissei (6) - Otake Hideo (5) - Kitani (4) - Shusai (3) - Shuei (2) - Shuho (1) - Shusaku (0)
- Hans Pietsch (6) - Yoda Norimoto (5) - Go Seigen (4) - Karigane (3) - Shuei (2) - Shuho (1) - Shusaku (0)
Hans Pietsch being at (6) is very potent, of course. That puts at least Emil Nijhuis, Victor Bogdanov and Catalin Taranu at (7). If you additionally include games that happened before he defeated Yoda (which was 27 June 1997), then there are many players that have defeated him before he became pro (many when he was still a kyu player). Such games are not in the European Go Database, which only goes back to 1996.