Up

# Shusaku Numbers

The Shusaku number of a go player is their distance from Honinbo Shusaku, when two players have distance 1 if they have played a game of go together. Some discussion is found at Sensei's Library.

This concept is modelled after that of Erdős number for mathematicians, their distance from Erdős when two mathematicians have distance 1 if they have a joint publication. The Sensei's Library page also mentions the Erdős go number. I (aeb) have Erdős number 2 and Erdős go number 1, but no kifu to prove it.

Usually it is easy to prove that two mathematicians have a joint paper, but it is not so clear how one should prove that two people played go together at some point in time, especially when these people need not be pros. For the present page my criterion was that I have seen a game record (kifu, SGF).

## Paths on the Sensei's Library page

From Sensei's Lib and other web sources one finds the tree

• 0: Honinbo Shusaku
• 1: Honinbo Shuho (Murase Shuho, sgf)
• 2: Honinbo Shuei (sgf)
• 2: Kita Fumiko (?)
A game between Shuho (died 1886-10-14) and Kita Fumiko (born 1875-11-16) is unknown, but Kita Fumiko (Hayashi Fumiko) played Iwasaki Kenzo (sgf), so Kita Fumiko really has Shusaku number 2.
• 3: Shiratori Sumiko (?)
• 4: Bob McGuigan (?), Michael Redmond (sgf)
A game between Kita Fumiko and Shiratori Sumiko is unknown, but Michael Redmond played Iwamoto Kaoru (sgf), so Michael Redmond really has Shusaku number 4.
• 3: Sugiuchi Kazuko (?, pupil of Kita Fumiko)
• 4: Antti Törmänen (sgf)
• 2: Oscar Korschelt (?)
• 3: Bruno Rüger (?)
For Oscar Korschelt and Bruno Rüger, see Wikipedia.
• 4: Christian Zak (?)
• 1: Iwasaki Kenzo (Ebizawa Kenzo, sgf)
• 2: Honinbo Shusai (sgf)
• 3: Felix Dueball (sgf)
• 4: Günther Cießow (?)
A game between Felix Dueball and Günther Cießow is unknown, but Günther Cießow played Segoe Kensaku (sgf), so he really has Shusaku number 4. See also Wikipedia.
• 3: Fujisawa Hosai (Fujisawa Kuranosuke, sgf)
• 3: Fujisawa Shuko (Fujisawa Tamotsu, sgf)
• 4: Cho Chikun (sgf)
• 5: Alexandre Dinerchtein (sgf), Shin Jinseo (sgf)
• 4: Lee Changho (sgf), Yamashiro Hiroshi (sgf), Yamashita Keigo (sgf)
• 3: Go Seigen (sgf)
• 4: Takemiya Masaki (sgf)
• 5: Alberto Rezza (?)
• 4: Kano Yoshinori (sgf)
• 5: Alain Wettach (?, see Belgo 78)
• 4: Herb Doughty (?)
• 5: Paul Erdős (?)
• 3: Iwamoto Kaoru (sgf)
• 4: Harry Fearnley (?), James Kerwin (?), Jan van Rongen (?), Ronald Schlemper (sgf)
• 3: Kajiwara Takeo (sgf)
• 4: Nie Weiping (sgf)
• 3: Kitani Minoru (sgf)
• 4: Kobayashi Chizu (sgf)
• 5: Iyama Yuta (sgf)
• 3: Miyashita Shuyo (sgf)
• 4: lloyd (?)
• 3: Nakagawa Senji (Nakagawa Kamesaburo II, sgf)
Pupil of Shuho.
• 3: Sakata Eio (sgf)
• 4: Yoda Norimoto (sgf)
• 5: Hans Pietsch (sgf), Lee Sedol (sgf)
• 3: Segoe Kensaku (sgf)
• 4: Cho Hunhyun (sgf)
• 5: Nakamura Sumire (sgf)
• 3: Shimamura Toshihiro (sgf)
• 4: Chen Zude (sgf)
• 4: Kudo Norio (sgf)
• 5: Guo Juan (sgf)
• 3: Takagawa Shukaku (sgf)
• 4: Juergen Mattern (sgf), Kato Masao (sgf), Sugiuchi Masao (sgf)
• 3: Yasunaga Hajime (sgf)
• 4: Matthew Macfadyen (?, see bgj056)
• 5: T Mark Hall (sgf), Ewart Shaw (?)
• 2: Kadono Kamesaburo (Nakagawa Kamesaburo I, sgf)
• 2: Karigane Junichi (sgf)
• 3: Hashimoto Utaro (sgf)
• 3: Kikuchi Yasuro (sgf)
• 4: Dave Sigaty (?), Frank Janssen (sgf), Nakazono Seizo (sgf)

## Paths derived from the present collection of SGFs

Below an automatically generated list with (upper bounds for) Shusaku numbers of various players. The links are to SGFs that prove the claimed Shusaku number. The current directory contains about thirty games, mostly from GoGoD, that help to decrease some value. Players who only have connections via games played before 1800 were not listed.

Making the list is straightforward in principle, but there are things to watch out for. If two players both play Anonymous, or a go program like Many Faces of Go, they do not get distance two. Names like Hayashi Monnyu or Nakagawa Kamesaburo do not uniquely identify the player. On the other hand, many players have several names. No doubt there will be further problems.

Shusaku