Handicap for smaller board sizes
Table of contents | Table of diagrams Two handicap stones Three handicap stones Four handicap stones Five handicap stones Handicaps are placed in similar order as on 19x19 board |
Handicaps and komi for smaller boards
First possibility
Regarding handicap games, the following table gives one possible way of allocating handicap and komi on 13x13 boards. First column: Strength difference on 19x19 goban, second column, handicap on 13x13 goban, third column, komi to white.
Difference 13x13 Komi Difference 13x13 Komi 0 0 5.5 10 4 5.5
1(*) 0 5.5 11 4 2.5 2 0 2.5 12 4 0.5 3 0 0.5 13 5 5.5 4 2 5.5 14 5 2.5 5 2 2.5 15 5 0.5 6 2 0.5 16 6 5.5 7 3 5.5 17 6 2.5 8 3 2.5 18 6 0.5 9 3 0.5 19 6 -3.5
(*) In the case of a one stone difference in strength, the weaker player takes black and plays first.
Second possibility (Tim Hunt)
On RGG, Tim Hunt posted his recommendations
Grade 13x13 board 9x9 board Difference Handicap Komi Handicap Komi 0 1 6 1 6
1 1 2 1 4 2 1 -2 1 2 3 2 4 1 0 4 2 0 1 -2 5 2 -4 1 -4 6 3 2 2 4 7 3 -2 2 2 8 4 4 2 0 9 4 0 2 -2 10 4 -4 2 -4
axd: With an exception for a discontinuity at D=0, for 9x9 this corresponds to following formulae:
H9= 1 + (D-1 div 5) K9= ((10-2*(D mod 5)) mod 10)-4
Note: the 10 term is not needed in combination with mod 10, but in e.g. M$ Access goes wrong without it.
If someone has an easier method, that avoids having to struggle with formulae or carry a table, that would be appreciated.
Third possibility (AGA)
There is a list of handicaps for small boards used by the American Go Association at AGA Handicaps.
Cambridge club
The Cambridge club (see http://www.cam.ac.uk/societies/cugos/ for more details) uses a different system for its end-of-term 13x13 handicap competitions. These are played with fast time limits of 10 minutes each. In that case
2.5 grades = 1 handicap stone
Old Japanese Recommendation
Around 1985 there was an article in the Japanese magazine Igo Kurabu by Ishikura Noboru (now 9p) on komi and handicaps for both 9x9 and 13x13 boards. His recommendations were based on the results of many pro-pro games on these boards. Here is a table summarizing his recommendations:
Difference in strength 9x9 13x13 handi komi* handi komi*
0 1 5.5 1 5.5
1 1 3 1 0 2 1 0 1 -5 3 1 -3 2 5 4 1 -6 2 0 5 2 3 2 -5 6 2 0 3 5 7 2 -3 3 0 8 2 -6 3 -5 9 3 3 4 5 . . . . . . . . . . . . . . . 30 8 0 11 5
*komi given by Black, so negative number means reverse komi.
Links
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http://www.timhunt.me.uk/go/handicaps/
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http://jakobsen.dyndns.dk/edo/pages_english/handicaptables.htm