Ai favors white?

From the very beginning of this game, white has 60%, black 40%.
Is it that i don’t understand or is it a bug? Or is that the AI knows the result already (let me doubt)?

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if komi is not perfect, one of sides is inevitably has more chances
only integer komi may be perfect

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@stone_defender is correct. When komi is a not an integer, then one player has an advantage from move one, however slight. The AI thinks that player is White.

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these % make little sense for humans by the way
AI that is close to perfection may give white 99% for example

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How should i use the info? Is it correct process to deduce that difference all along the game?

you don’t, use Score metric

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So that should br suggested for these retransmission as default setting.

it is useful to know which move gives more chances to win the game by at least 0.5 points

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Ok. I usually use the points indicator, so my confusion.

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If you toggle win % to score it makes more sense to humans

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I suppose there’s always the tiniest possibility that in Japanese rules or Chinese rules in practice (not with OGS superko) that optimal play just leads to draw (no result etc) by triple ko or other infinite repetition even with a half point in the komi :slight_smile:

So maybe a very very slight chance that perfect ai might score the game 50/50 :stuck_out_tongue:

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Well it’s clear now. In some way it’s bit insulting us humans. If i saw, let say 50.1% i would say great, but 60% doesn’t look like a small matter.

Its possible to make white side of AI play weaker, then chances will be 50%
but then after game, it basically will mean, that black will get review level IV and and white will get review level III

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That game (European Championship Semifinal) is with 7.5 komi under Chinese rules (where score difference on the board is most often odd).

That (usually) comes down to black needing to make at least 9 points more on the board to win.

There is a reason that 7.5 komi is called a “large” komi (AI would even say too large, by 1 point according to KataGo review level IV).

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I think that, although your number of “9” points is technically correct with the right interpretation, it might easily be misleading. There is almost always (assuming normal dame parity, but there is in fact no difference for the odd parity!) exactly a 1 point difference between Japanese and Chinese komi. Since black needs to win by 7 points of territory on the board to get a win in Japanese rules, people might reach the wrong conclusion that they need 2 more points of territory under Chinese rules. In reality, Chinese rules only require one more point of territory for black to win.

This is because, as you say, under normal parity of dame (almost always) the score difference is odd under Chinese rules. But what that difference is can actually be predicted reliably from the territory-counting, Japanese style score (unless players passed early, or there is different territory in seki, dame-fight for the last ko or some other very exotic difference kicks in): when the Japanese score difference on the board is even, the Chinese score is that same difference but adding one point for black: that is because precisely in those cases, black gets the last dame and gets an extra point (when white gets the last dame instead, the scores match, because they both played the same number of stones).

Thus, if you get a difference of Black +7 points counting Japanese style, you will get Black +7 points counting Chinese. If you get Black +8 or Black +9 when counting Japanese style, in BOTH cases you will get Black +9 in Chinese rules. Thus, Chinese komi effectively means that Black needs to win by +8, instead of +7 as in Japanese rules (always counting territory).

Still, AI seems to agree that 6,5 is a great Komi (under territory scoring): it seems that strong AI under self play finds the most balanced games with that komi (slightly preferring 6 over 7 when going for integer values), thus 7,5 would be “one point too good for white” at the very top level (while the old komi of 5.5 would be one point too good for black).

Of course this is strong evidence that “perfect” komi for ideal players would be 6, but it is a tough call between 6 and 7 so 6,5 might be more balanced than 6 actually for human play (apart from being able to break ties).

Due to the dame parity, pure area scoring rules (and not “hybrids” like Lasker Maas, the “Taiwan Rule” or Button Go) only allow to set komi to 5,5 or 7,5 (6,5 would make a difference from 5,5 only very very rarely, as the chinese difference in score is very very rarely 6, that requires special odd seki).

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AlphaGo, LeelaZero and KataGo all agree that 7.5 is too much.

It seems that 6 - 7 komi is more fair than 7.5 komi under all rule sets. Why is the fact that 6.5 komi is about the same as 5.5 komi under Chinese rules, considered a stronger argument than fairness of komi?

(also see What is the "Strong bot based fair komi" for 19x19 using Japanese-like (for example, KataGo) rules - #7 by hexahedron stating that 6.5 komi may be fairest under Japanese rules and 7 komi may be fairest under Chinese rules, according to KataGo)

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I don’t think it is considered stronger, it just explains the historical jump that went from 5,5 directly to 7,5 when humans experimentally found 5,5 to favor black: both rulesets, which used 5,5 at the time, increased komi. Since 5,5 to 6,5 would be a tiny increase because only in very very rare cases makes a difference, they went for 7,5. This was long before strong bots existed.

As to why not change it once again today, to lower the Chinese komi… Well I do not know, maybe one day, they will decide to change it again :stuck_out_tongue: If they are to tinker with komi again, maybe introducing “Button Go” (or the basically equivalent Taiwan Rule) to allow for meaningfully setting the Chinese komi to 6,5 might be even more interesting than just bringing it back to 6,5 (which is almost the same as the old 5,5. Though that might still be slightly more fair than 7,5).

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Yay button go. I hope they adopt button go. :slight_smile:

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I’m rooting for integer komi. 6 for Japanese rules and 7 for Chinese rules :grin:

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Me too. It bugs me that otherwise tied games are arbitrarily awarded to white. Would love to see AGA adopt integer 7 komi. I feel like China and Japan may be too traditional to change now… But Korea might :man_shrugging: wait and see

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