Scoring question 0.5 stone difference

See the game at Tournament Game: September 2022 - Double Elimination 19x19 (92681) R:1 (bklarson vs AlexandrS) - do I (White) need to throw in at D14 or not count it as a point?

Normally it would not be a point. But it is black’s turn, and for me to move again and throw in there, they would need to move again as well, keeping me 0.5 points ahead?

I suspect I’ve lost, but am not positive on how the scoring works here. Thanks for any feedback!

Hi @bklarson. D14 shoudln’t be counted as a point for white in Japanese rules.


D14 is a ko which should be finished before ending the game. Whoever wins it can connect the ko. In territory scoring it’s about having or losing one capture, in area scoring it’s about having or losing two stones, as far as I know.


Normally, White would have connected that ko, and Black would have passed. Black is not forced to fill in their own territory to give you a point back. They could even fill a dame instead.

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Can you provide a source or reason for this? I’m interested, but I know the Japanese rules aren’t that easy to comprehend.

I don’t have a source, but it seems obvious and intuitive. You usually win the ko by closing it. Those half point kos are played to get an extra prisoner, not for territory.



My feeling is that it’s similar to the example in Article 7 on dead stones which also features an unresolved ko.

Because the white stone in the game can be captured it should be treated as dead but left on the board for scoring, which means the point at D14 that should’ve been filled doesn’t count for territory.


But in that example (diagram 9) black’s whole group is dead too:

If the game ends in this way, the black group and the white stone are both dead.

Maybe diagram 10 serves as an answer:

2. If a player whose stone has been captured in a ko has passed for that particular ko
, the situation for that ko is the same as if the game had been resumed: the player may now capture in that ko again.

So black lost a stone, black passed, white passed and black could retake if the game was resumed? That would make it clear that white has to connect (otherwise black can retake), and therefore it is not a point. :man_shrugging:


Disputes regarding unfinished ko seems to have played a rule in formal codification of the Japanese rules.

The modern rules essentially requires the kos to be resolved. Left as is, the stone at E14 would be considered dead (but not removed, since it does not reside within any territory), and neither player gets any territory points for that ko.


This particular shape is even weirder, as an example of “anti-seki”. If both players have passed, then both the lone White stone and the Black stones are considered dead, but none are removed for counting purposes.

See Odd Cases 🤔 in the Japanese Rules - #3 by yebellz


Sure technically it’s weirder but I think it’s pretty much in the sense that there’s a stone or group that could be captured in ko but isn’t.

I’m not even sure I believe anti seki is a real term and isn’t some made up interpretation.

Maybe the D14 ko stone is also in anti-seki.

I don’t really see a formal explanation of the term

That specific position is mentioned in this translation of the commentary of the Japanese rules.

The term “anti-seki” does not appear in that text, so that specific phrase seems to have been coined elsewhere, but it is naming a concept that does explicitly appear in the rules text.

An open and unconnected ko can never give a point to W as in the original position. The reason is simple (and need no complicated L/D reasoning):

B can simply pass, and if W doesn’t fill the ko B can retake it with his next move. (He can resume the game whenever necessary, like if W also passed and that caused a stop. On some servers like IGS the game only stops on three passes to make this easier.)

I know, I linked two places with that specific position also.

To be honest it’s not clear what it’s naming. Is it the name of that specific position, like bent-4 in the corner? Is it naming a more general concept?

After passing, all Ko limitations should have been removed.

If White insists on not filling in the Ko, Black should be able to retake.

However this begs the question of whether this is properly implemented on the server.

Edit: it is!

It is properly implemented in one sense, but I kind of saw it more like a bit of an exploit.

Maybe it isn’t though.

There is some ruleset dependencies though. I think in Japanese rules you can recapture kos on resuming, but in rules with superko I don’t think you can make the board repeat even after passes.

The thing that isn’t properly implanted in Japanese rules is that when you click resume it should be your opponent that gets to play first.

Anyway as an example without linking the game

Black passes in this position, they go to scoring then resume and white retook the ko. This happen a few more times until white could basically live in the corner

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Indeed. I just artificially recreated this situation on the Beta website, and there was no problem there.

Upon resuming the game White should fill in, or Black should retake. That way neither can try to “cheat out” an extra point.

With area scoring, it actually doesn’t matter if the Ko is filled or not, so it wouldn’t be an issue. Rulesets with strict positional superko (that does not account for prisoners) usually use area scoring anyway.

I mean it depends on what you mean by doesn’t matter.

Is it still a point to fight over? Yes, so it should be filled or fought over.

Could it be scored as if it was filled? Yes, but it should still be filled realistically unless there was some weird tactical superko position where you don’t want to fill it.

True. What I mean specifically is “Same score in practice, OGS-wise”.

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