[Rare] Seki on whole board

cool right?


Cool! A couple of funny things about it:

  1. No score “yet”?
  2. The estimate is W+6.0 instead of being close to a half-integer.
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Also curious to see what the more playouts review says.

Also noted in the game chat that white gains a point by capturing the J7 stone

W+5.6 ~ W+5.5 which would be if the stone was captured I suppose.


Shouldn’t J7 be marked dead anyway? AI doesn’t seem to want to capture it in it’s recommended variation.

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(white to move)

capturing the stone gives more score than pass, but AI doesn’t care

Technically, dead stones within territory nullified by seki need to be manually captured in order to count as a capture.


Oh, right, I forgot. So I wonder why AI doesn’t bother with it then:

I don’t know. Maybe the AI does not fully learn that particular quirk of the Japanese rules?

However, @stone_defender’s shared a screenshot with analysis that seems to indicate otherwise?

I think KataGo knows that J7 should not be marked dead under Japanese rules. It wants to capture at J8 on move 74:

White won the game by 4.5, but he would have won by 5.5 if he had captured.


if we play on real board (offline), the black one stone (J7) will be returned to fill black own territory, if both player agree that it is a dead stone. so I think its not necessary to capture it.

but if we play online, we need to check if the scoring system can mark it as a dead stone but also mark the territory as no point.

If the game is played IRL under Japanese rules and black agrees J7 is dead without white capturing it before passing, black is making a mistake that costs him a point. If white doesn’t capture it before passing, J7 should stay on the board during counting and not go into white’s prisoner bowl or into black’s territory.

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How so ?

It’s how the Japanese rules work. No points in a seki, and that includes any stones left stranded in an eye area of a seki.

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I know, but if black refuses to consider it dead then White will just resume and capture it anyway. Black might as well agree.

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Black could, but I’ve seen many players IRL who would be adamant as black that white captures it before passing, just to finish the game properly.

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in real game, we move the stones at the and of the game to make it easier to count. so it doesn’t include the J7 stone…? I see

Yes, many dozens of times. But I don’t remember games in Japanese go salons where white would refuse to capture it before passing. If it happens, it’s usually players who don’t know the rules very well.


Technically, that stone should not be removed, but I think that in many casual games the players would simply agree to remove, even if that is different than what the rules specifically say, and because…



It can actually be that you can end up with a number of captures too to maintain seki.


Near the end of the game say, white can capture two stones, then black needs to throw in another that white can capture. So that’s three prisoners :slight_smile: