Is this seki?

[calantir]

Hello,

I am playing a game on OGS and was wondering if the bottom left corner is potentially seki. Does it depend on the rule system?

http://ggs.nova.gs/napi/sgf/424591

[HermanHiddema]

Well, it seems you are linking directly to the game record on OGS, so it is updating with moves.

The move the question is about, I assume, is W296 @ A2

- Is it a potential seki?
Only if black makes a mistake. He didn't.

- Does it depend on the rule system?
No.

- Is it a good move?
Yes! White actually gained a point with that

[yoyoma]

Interesting position, it forces black to fill in the fake eye between his two real eyes. If not for the fake eye in the middle of black's group, white's move would not have gained a point!

[calantir]

Thanks! As black, I wasn't sure if I could leave it alone and still count it as territory or not. I was trying to find on sensei's library an explanation of this type of situation but it either wasn't there or I was too dense to see how it applied

[Kirby]

Thanks! As black, I wasn't sure if I could leave it alone and still count it as territory or not. I was trying to find on sensei's library an explanation of this type of situation but it either wasn't there or I was too dense to see how it applied

One explanation is:
1) As observed by the game sequence, black is able to live without seki (and capture the two stones). This is because black had enough outside liberties to capture the stones without putting himself/herself into self-atari. Result: Not seki (two stones are captured).
2) If black opts to "leave it alone", as you considered, after black's outside liberties are filled, it is impossible for black to capture the two white stones without playing self-atari. Result: seki.

Regardless of the ruleset, you don't get to count as captures stones involved in seki. Depending on the ruleset, you can sometimes count eyes in seki.

Therefore, only in option 1, above, does black obtain the points from the two captured stones. If black opts for option 2, above, the white stones are part of the seki and not counted as points.

[Bill Spight]

OT, but the losing play was W288. White does not need to protect the top right corner yet. White should push in at P-05. Black will have no better play than to reply, and that makes a difference of 1 pt.

[cyclops]

- Is it a good move?
Yes! White actually gained a point with that

No! (IMHO) W throws away the last chance to win the game. If W first fills B's outside liberties, B (8 kyu) may not notice the impending seki. Postponing the move is a good gamble if you know you are losing.
If W wants to be really sneaky he could fill casually all dame in random order checking his watch indifferently until the trap goes off. Don't know about sportmanship though.

[calantir]

Kirby-

So if I understand right, with option 2, I would have four points of territory, counting the white stones as seki, but with option 1, where I fill in my own false eye and then capture the two white stones, I have three points of territory and two points from the captured stones. So option 1 is better.

Bill -

This is my first time posting on the forum, but I have been lurking for a while. I hoped you would have an observation about the endgame. I don't think I've ever played a lower-scoring game with so much emphasis on the endgame. I was lucky to have noticed P-5 first!

[Kirby]

Kirby-

So if I understand right, with option 2, I would have four points of territory, counting the white stones as seki, but with option 1, where I fill in my own false eye and then capture the two white stones, I have three points of territory and two points from the captured stones. So option 1 is better.

In some rulesets, seki has no points. So with option 2, black lets it turn into seki and gets no points. Under rulesets where you get points for eyes in seki, black gets one point for his eye that has no white stones. So for option 2, depending on ruleset, you have 0 or 1 point as black.

With option 1, like you said, you get 3 points of territory, plus two for the captured stones.