Note to moderators: I'm using my personal page to display board configurations to prove a point in a forum post. Please don't flag this as off-topic, or whatever.
This is a pretty standard handicap, all would agree.
Here is the handicap offered in the first round of the handi-tournament on OGS I argue that this is excessive, even when the two players are 15 stones apart in strength.
Notice that to cram 9 stones into a 13x13, they must be much more densely placed, and there is very little possibility for White to create territory without a black making a catastrophic mistake. Either way, white must rely on trick plays, etc.
Here is the equivalent handicap stone density on a 19x19 board. This is a 25 stone handicap, and would be very hard to beat.
I argue that you could use this ratio (where 9 stones on 13x13 is equivalent to 25 stones on 19x19) to convert regular 19x19 handicaps based on rank to proper 13x13 handicaps.
Basically, 1 stone on 13x13 is worth 2.9 stones on 19x19. Any fractional remainder should count as a full stone. Take these examples with players SenseiSam? and NormanDNovice.
- If SenseiSam would give Norm 9 stones on 19x19, he should give 4 stones on 13x13. (Notice that this would offer the same handicap stone density as 19x19, with each handicap stone separated by 5 empty spaces)
- If Sam would give Norm 6, 7, or 8 stones on 19x19, it would be 3 stones on 13x13.
- If SenseiSam would give NormanDNovice 3, 4, or 5 stones in 19x19, he should give 2 stones in 13x13
- For big handicaps, like 12-15 stone handicaps, you can add a stone in the center.
- For handicaps with a range of values (ie 6, 7, or 8 all translate to 3) you can adjust the komi to handle the difference in rank.