Determining big komi

[Joaz Banbeck]

Is there any formula or rule ( or table ) for determining a komi between two players of any strength? Assuming that no handicap is used. The players might be 15kyus or dans or pros. I'm looking for a way to get a competitive game, regardless of relative strength, using only komi.

[topazg]

I don't think so, and it depends very much on time controls.

My experience is 15 points in blitz, 10 points in non-blitz real time games, and 6 or 7 in correspondence based games per stone difference in strength.

[phrax]

My limited non-blitz experience has 10 points/stone being about right as well.

[Jonas]

I believe it is not possible to trade handistones with komi.

[Bill Spight]

Is there any formula or rule ( or table ) for determining a komi between two players of any strength? Assuming that no handicap is used. The players might be 15kyus or dans or pros. I'm looking for a way to get a competitive game, regardless of relative strength, using only komi.

With territory rules:

Dan difference Reverse komi
-------------- ------------

1 6.5
2 20.5
3 34.5
4 48.5
5 61.5
6 74.5
7 87.5
8 99.5

I wouldn't trust anything beyond that, and I would not expect precision, anyway. As komi increases, the difference per dan reduces, but nobody really knows how.

Also, komi should reduce with the strength of the White player, but nobody really knows how.

[Joaz Banbeck]

I believe it is not possible to trade handistones with komi.

I think that it is logically necessary that this is true. If player A plays player B with no handicap, there will be a result, and that result - assuming nobody resigns - can be quantified. That quantity is komi. As a practical matter, large numbers of games could be played to get a good average.

If you mean that it is not possible to trade at a fixed ratio, I'd agree.

I'm not suggesting that it is a simple formula, that we could say that "one handical stone = 14 komi". A stone may be worth 15 points when a pro uses it, less when you or I use it, and totally squandered by a 30K. I strongly suspect that such a formula would not only have to take into account the relative strengths of the players, but their absolute strength also. ( That is why the initial question mentions a table )

[topazg]

I believe it is not possible to trade handistones with komi.

I think that it is logically necessary that this is true. If player A plays player B with no handicap, there will be a result, and that result - assuming nobody resigns - can be quantified. That quantity is komi. As a practical matter, large numbers of games could be played to get a good average.

I'm not suggesting that it is a simple formula, that we could say that "one handical stone = 14 komi". A stone may be worth 15 points when a pro uses it, less when you or I use it, and totally squandered by a 30K. I strongly suspect that such a formula would not only have to take into account the relative strengths of the players, but their absolute strength also. ( That is why the initial question mentions a table )

In Kage's chronicles of handicap go, both players make comment (Kogeyama and his opponent for most of the games) agree a 3 stone handicap would be expected to lead to a 30 point difference. Their 5 stone games left me with the impression that 50 was about accurate - there isn't much data to go with here, but I suspect it isn't 15 points per stone equivalent at professional level if these games are anything to go by.

[gowan]

Everything depends on probability of winning given two ranks. That's how things work in tournaments with handicap games since ranks themselves are based on probability of winning. A "proper" handicap in theory would make probability of winning equal 50%. I think that's the best you can hope for with reverse komi. Because it is a probabilistic thing the formula will never be correct for any particular pair of players. We all know of people who can force weaker players to take a higher handicap than the rank difference would assign. It is also recognized that stone handicaps aren't really linear with rank difference.

The only way to get an approximation formula would be to have a database of thousands of even games, played out to a numerical result, between players of all different ranks. Even games because the reverse komi is supposed to compensate for rating difference in even games. With such a database some kind of multivariable regression or contingency table analysis might yield a useable formula. The trouble is in general we don't play even games when ranks are very different and in practice too many of these games would end in resignation.

[Harleqin]

You cannot simply average the score outcomes, because the playing style is dependent on who is leading and by how much. You need to set a komi before the game, then play a large number of games to gather the winning percentages; set a different komi, repeat.

[Li Kao]

And if you have two pairs of players which are evenly matched with n handicap this does not mean they are evenly matched with m komi. It depends a lot on the play style.

[Joaz Banbeck]

I believe it is not possible to trade handistones with komi.

Obviously it is possible since people are doing it.
If you have some point, and not only was saying the first thing that got into your head, please expound.

Note that Jonas' location is Germany, so English is probably not his native language. I don't think we can take that statement literally in English. I think that he means that it is not possible with a simple ratio.

[Bill Spight]

In Kage's chronicles of handicap go, both players make comment (Kogeyama and his opponent for most of the games) agree a 3 stone handicap would be expected to lead to a 30 point difference. Their 5 stone games left me with the impression that 50 was about accurate - there isn't much data to go with here, but I suspect it isn't 15 points per stone equivalent at professional level if these games are anything to go by.

The estimate of 10 pts. per stone dates to the time when komi was 4.5. Each stone difference is approximately worth twice komi, at least at first. Now that we know that komi is larger, so is the approximate size of the difference.

Edit: Back in the 70s I analyzed some pro-pro handicap games (admittedly a small sample) and found an average difference per stone of about 13.5 points through 9 stones. That's when I predicted a komi of 6.5 by the turn of the century. Almost!

BTW, I once gave 100 pts. reverse komi instead of giving 8 stones. I won by about 100 points.

[Horibe]

I expect it is quantifiable. Between two particular players, the ability, usually black's, to take advantage of the advantage may differ, but so does the ability to use handicap stones.

I simply think it is not a useful idea. Fun perhaps, but not useful.

If a weaker player wants to work on even game opening - then play an even game opening. An opening where a strong player is trying to make up 50 points is not an even game opening.

If a weaker player wants to work on fighting - then fight with handicap stones - the techniques learned are valid in even games. You still have to deal with strong attacks on weak stones, but you also get to attack from strength against strong responses - something you cannot set up in an even game.

Playing to coast out a huge komi teaches you very little, certainly not as much as other methods.

[Phelan]

Playing to coast out a huge komi teaches you very little, certainly not as much as other methods.

It can teach you how to count, I think. For players that usually don't count, knowing they have a reverse komi advantage might make them start counting.

[Horibe]

Playing to coast out a huge komi teaches you very little, certainly not as much as other methods.

It can teach you how to count, I think. For players that usually don't count, knowing they have a reverse komi advantage might make them start counting.

The score is the score, if they do not count in games when they receive normal komi, why count when you have reverse.

Better to tell the weaker player - "If we finish and count a game and you are losing by more the 20 - then (insert punishment). In a club when weaker players are competing to play the local strong guy, this method of encouraging timely resignation teaches counting and adds efficiency to the teachers time.