Fair komi without ties

[moha]

Button go, anyone?

Komi 7 simply.

[luigi]

Button go, anyone?

I've mentioned this multiple times in this thread already. It would be the perfect solution, but no one seems excited about it.

[John Fairbairn]

With the 4.5 komi the median result on the board was between 6 and 7 for Black, and with the 5.5 komi the median result was between 6 and 7. No fine tuning.

Bill: I'm not sure what you are saying here, but my first impression is that this only shows that pros tend to count out the game when the result falls within a certain band. You need to include resigned games to complete the picture.

On that point, I toss out some stats from GoGoD for some of the various komis (from year dot to 2017-10, jigos excluded):

No komi
10702 games
W+ 4032 (of which W+R = 1989, or 49.3% of W+)
B+ 5612 (of which B+R = 2932, or 52.3% of B+)
W+ 37.7% vs B+ 52.4%

2.5 Japanese komi
362 games
W+ 149 (W+R= 84 or 56.4%)
B+ 180 (B+R = 102 or 56.7%)
W+ 41.1% vs B+ 49.7%

3.5 Japanese komi
60 games
W+ 28 (W+R = 15 or 53.6%)
B+ 32 (B+R = 20 or 62.5%)
W+ 46.7% vs B+ 53.3%

4.5 Japanese/Korean komi
2685 games
W+ 1208 (W+R = 645 or 53.4%)
B+ 1477 (B+R = 928 or 62.8%)
W+ 45.0% vs B+ 55.0%

5.5 Japanese/Korean komi
21953 games
W+ 10347 (W+R = 5544 or 53.6%)
B+ 11563 (B+R = 6765 or 58.5%)
W+ 47.1% vs B+ 52.7%

6.5 Japanese/Korean komi
26521 games
W+ 13133 (W+R = 8814 or 67.1%)
B+ 13365 (B+R = 9080 or 68.0%)
W+ 49.5% vs B+ 50.4%

2.75 Chinese komi (said to = Japanese 5.5)
7471 games
W+ 3499 (W+R = 2355 or 67.3%)
B+ 3972 (B+R = 2902 or 73.1%)
W+ 46.8% vs B+ 53.2%

3.75 Chinese komi (said to = Japanese 6.5)
15496 games
W+ 8160 (W+R = 6425 or 78.7%)
B+ 7327 (B+R = 5792 or 79%)
W+ 52.7% vs B+ 47.3%

As regards jigo: when komi was 0 there were 274 jigos out of 10702 games (2.6%), and when komi was 5 there were 9 jigos out of 962 games (0.9%).

Others can interpret these data better than I, but it seems obvious that increasing the komi has increasingly benefited White (the slight blip for 3.5 may be ignored for too few games).

However, the sudden leap in White's favour for 3.75 Chinese komi seems potentially anomalous, at least when compared to Japanese/Korean 6.5, and also considering that JK 5.5 vs Chinese 2.75 gives similar results. I can offer no explanation for this, though it does seem to gel with what Chinese pros say about White's advantage. However, in my innumerate naivety I can't help but notice that 2 x 2.75 = 5.5 whereas 2 x 3.75 = 7.5 and not 6.6. In any case, Japanese/Korean 6.5 komi produces the closest B+ vs W+.

The small number of jigos surprised me.

It is noticeable that Black always seems more likely to resign, but Chinese players are very significantly more inclined to resign (with either colour) than JK players. As I've suggested before (on the basis of talking to Chinese players) this may have something to do with the tedium/inconvenience of counting up the Chinese way, but it's become more marked under the larger (?more unbalanced) komi so it may also have something to do with that.

[HermanHiddema]

3.75 Chinese komi (said to = Japanese 6.5)

...

However, the sudden leap in White's favour for 3.75 Chinese komi seems potentially anomalous, at least when compared to Japanese/Korean 6.5, and also considering that JK 5.5 vs Chinese 2.75 gives similar results. I can offer no explanation for this, though it does seem to gel with what Chinese pros say about White's advantage. However, in my innumerate naivety I can't help but notice that 2 x 2.75 = 5.5 whereas 2 x 3.75 = 7.5 and not 6.6. In any case, Japanese/Korean 6.5 komi produces the closest B+ vs W+.

I'm curious who's claiming Chinese 3.75 = Japanese 6.5. Chinese 3.75 should be equivalent to 7.5 Japanese, not 6.5 Japanese (which would be 3.25 Chinese).

Perhaps some people were confused by the fact that Japan went from 5.5 to 6.5 and China went from 2.75 to 3.75 at around the same time?

[Bill Spight]

With the 4.5 komi the median result on the board was between 6 and 7 for Black, and with the 5.5 komi the median result was between 6 and 7. No fine tuning.

Bill: I'm not sure what you are saying here, but my first impression is that this only shows that pros tend to count out the game when the result falls within a certain band. You need to include resigned games to complete the picture.

I am including resigned games. The median (50-50 point) does that.

My guess is that the changes in strategy based upon changes in komi produce more resignations than small losses, which I think is something that you have in mind. However, that may well not change the median, if it is close to komi. The changes in strategy need to change small losses into wins to be effective.

[dfan]

"In my experience and the experiments we've run, komi 7.5 is very balanced, we only observe a slightly higher winrate for white (55%)."

Source from DeepMind's Julian Schrittwieser

https://www.reddit.com/r/MachineLearnin ... ittwieser/

That's a pretty high win rate! 55-45 is just about the same as White's advantage in chess (counting draws as a 0.5-0.5 tie), and everyone likes to point to that as one of the disadvantages of chess.

[billyswong]

Button go, anyone?

I've mentioned this multiple times in this thread already. It would be the perfect solution, but no one seems excited about it.

I guess button go being unpopular is because upon introduction of a new object "button", people think of the game as a go-variant, not seeing it a 'proper' ruleset of go anymore, so it's a very perceptual thing.

So Luigi your first proposal "first passer wins ties" may be more likely to get considered seriously into common use. As long as a pass lifts ko bans, I guess it will be okay?

[Bill Spight]

Button go, anyone?

I've mentioned this multiple times in this thread already. It would be the perfect solution, but no one seems excited about it.

I guess button go being unpopular is because upon introduction of a new object "button", people think of the game as a go-variant, not seeing it a 'proper' ruleset of go anymore, so it's a very perceptual thing.

I don't think that button go is unpopular; people are just unaware of it.

The equivalent of button go has already been played in international competition. IIUC, go in the Mind Sport Olympiad uses area scoring but if White passes first White gets an extra point.

It is easy to modify AGA scoring to incorporate the equivalent of a button. Under current rules White must pass last, handing over a pass stone. Under the equivalent of button go White must pass last only if Black made the first pass, otherwise Black must pass last. OC, with the pass stones, territory counting is used.

[luigi]

I don't think that button go is unpopular; people are just unaware of it.

The equivalent of button go has already been played in international competition. IIUC, go in the Mind Sport Olympiad uses area scoring but if White passes first White gets an extra point.

It is easy to modify AGA scoring to incorporate the equivalent of a button. Under current rules White must pass last, handing over a pass stone. Under the equivalent of button go White must pass last only if Black made the first pass, otherwise Black must pass last. OC, with the pass stones, territory counting is used.

But, as you explained in some other thread, neither of those is completely equivalent to Button Go. They're just logical implementations of territory scoring. Or am I missing something?

[Bill Spight]

I don't think that button go is unpopular; people are just unaware of it.

The equivalent of button go has already been played in international competition. IIUC, go in the Mind Sport Olympiad uses area scoring but if White passes first White gets an extra point.

It is easy to modify AGA scoring to incorporate the equivalent of a button. Under current rules White must pass last, handing over a pass stone. Under the equivalent of button go White must pass last only if Black made the first pass, otherwise Black must pass last. OC, with the pass stones, territory counting is used.

But, as you explained in some other thread, neither of those is completely equivalent to Button Go. They're just logical implementations of territory scoring. Or am I missing something?

The first method, which uses area scoring, adds on average 0.5 pt. to White's score. It is true that the result is an integer score, but you can combine it with 6.5 komi. 6.5 + 0.5 = 7, so in effect you have a 7 pt. komi with a button.

The AGA modification is actually an implementation of double button go, as it is used with territory counting. It also adds on average 0.5 pt. to White's score, and can be combined with a 6.5 komi.

While you can regard button go as a form of territory scoring, it avoids the complications of territory rules, as it does not stop play when plays become negative by territory scoring, so that kos and life and death can be resolved by play. But you can also regard button go as a form of area scoring. Button go is a hybrid of both forms of scoring.

[moha]

So Luigi your first proposal "first passer wins ties" may be more likely to get considered seriously into common use.

Code: Select all

komi 5.5               :  B wins ties
komi 7.5               :  W wins ties
button                 :  first passer / dame parity wins ties
somebody had a ko idea :  first passer in final two passes wins ties (may be more tricky)
or                     :  more time left wins ties
or even                :  lower rating wins ties
or politely            :  women or elder wins ties
or just                :  dicethrow wins ties
all to avoid reality   :  no winner in ties :)

BTW, even with the button isn't there cases where ko threats decide the winner, after competitive play is over? I'm not sure such behaviour is desirable.

[luigi]

Let A be a form of area scoring where, if White passes first, White gets an extra point. Komi is 6.5.

Let B be a form of territory scoring with pass stones where White must pass last if Black made the first pass and Black must pass last if White made the first pass. Komi is 6.5.

Let C be button Go (area scoring) with komi 7.

Bill, if B (a modification of AGA rules) is an implementation of double button Go, as you say, how can it also be equivalent to C?

I'm pretty sure A and B are fully equivalent, and I view them as the purest and best forms of territory scoring (much preferable to the convoluted Japanese rules, which I would replace with one of these right away). But you already convinced me that these weren't fully equivalent to C when you said:

But there are one[-sided] dame, which do not have to be played before the button. For instance, suppose that Black has a one way dame and a territory score of 6. Because she does not have to play the one way dame before the button is taken, she will get an area score of 7.5. After the button is taken, she will have a score of 6.5, and then she takes the one way dame for one more point. Also, there are ko fights that may not be finished until after the button is taken, and they may be exceptions, as well. In addition, it is possible to have positions on the board that are equivalent to a button (I have constructed one), so that who gets the button does not matter.

I think this argument applies to Japanese rules as well as A and B. Under any of those rulesets, if Black passes before playing the one-sided dame, White will just end the game by passing in return. As a result, Black wins by 6 on the board and loses by 0.5 after applying 6.5 komi. Compare this to C, where Black wins by 0.5 by taking the button first and then playing the one-sided dame, as you pointed out.

[Bill Spight]

BTW, even with the button isn't there cases where ko threats decide the winner, after competitive play is over? I'm not sure such behaviour is desirable.

Those situations can arise with a modification of AGA rules that attempts to make a form of territory scoring but does not dictate three passes to end the game under some circumstances. The modification of AGA rules that I set out above avoids those problems by dictating three passes under some circumstances. It just does not always force White to make the last pass.

The problematic situation arises this way. A pass costs one point by handing over a pass stone, and two passes in succession end the play. Player A passes. Player B does not want to pass last, so plays a ko threat, which Player A must answer. Now Player B passes, and if Player A makes the last pass he is penalized one point. So Player A makes a ko threat if possible, and we have a pass fight. We agree that that is undesirable.

[Bill Spight]

Let A be a form of area scoring where, if White passes first, White gets an extra point. Komi is 6.5.

Let B be a form of territory scoring with pass stones where White must pass last if Black made the first pass and Black must pass last if White made the first pass. Komi is 6.5.

Let C be button Go (area scoring) with komi 7.

Bill, if B (a modification of AGA rules) is an implementation of double button Go, as you say, how can it also be equivalent to C?

I'm pretty sure A and B are fully equivalent, and I view them as the purest and best forms of territory scoring (much preferable to the convoluted Japanese rules, which I would replace with one of these right away). But you already convinced me that these weren't fully equivalent to C when you said:

But there are one[-sided] dame, which do not have to be played before the button. For instance, suppose that Black has a one way dame and a territory score of 6. Because she does not have to play the one way dame before the button is taken, she will get an area score of 7.5. After the button is taken, she will have a score of 6.5, and then she takes the one way dame for one more point. Also, there are ko fights that may not be finished until after the button is taken, and they may be exceptions, as well. In addition, it is possible to have positions on the board that are equivalent to a button (I have constructed one), so that who gets the button does not matter.

I think this argument applies to Japanese rules as well as A and B. Under any of those rulesets, if Black passes before playing the one-sided dame, White will just end the game by passing in return. As a result, Black wins by 6 on the board and loses by 0.5 after applying 6.5 komi. Compare this to C, where Black wins by 0.5 by taking the button first and then playing the one-sided dame, as you pointed out.

Yes, if taking the button counts as a pass for ending play, then there could be problems. That is why I do not advocate doing so. In fact, I have objected to ending play with two consecutive passes for over 20 years. Yasunaga, many years ago, proposed a three pass rule, and Ing has a four pass rule. But I think that the Mind Sports rules end play with two consecutive passes, and count "taking the button" as a pass. I am afraid that I am swimming against the tide.

Edit: Also, taking the button should lift any ko or superko ban.

[luigi]

Yes, if taking the button counts as a pass for ending play, then there could be problems. That is why I do not advocate doing so. In fact, I have objected to ending play with two consecutive passes for over 20 years. Yasunaga, many years ago, proposed a three pass rule, and Ing has a four pass rule. But I think that the Mind Sports rules end play with two consecutive passes, and count "taking the button" as a pass. I am afraid that I am swimming against the tide.

Now I'm confused. I think the main reason why C is different from A and B is that taking the button doesn't count as a pass for ending play. (EDIT: Nevermind. I think this is what you meant in the first place.)

Also, the Mind Sports rules don't use the button at all. Right?