[Rare] Double Ko - considered as seki?

Both players spent more moves on the triple ko, wasting their time until they agreed there are no points to count in that area.


Nice position! The game seems to use Japanese rules with 5.5 komi. The left would be a double ko seki in itself, but W’s outside ko changes everything.

If they keep fighting for it, the game is draw on repetition. If W stops fighting for the outside ko (as happened), B should connect it, and then all that remains is a double ko seki - B wins with his right side territory. So W shouldn’t do that, but keep fighting.

If B stops fighting for the outside ko, W (with his outside liberty) can first connect an internal ko and then kill the left since he takes first in the ensuing direct ko (but note that this is one point worse for W than if B simply ignored an internal threat to win the outside ko).

If this would be enough for W, B would have needed to keep fighting for the outside ko and accept repetition. However, W killing the left this way (starting with the costy internal connecting move) would still seem to lead to B+0.5 (B wins the outside ko meanwhile).

So if B stops fighting for the outside ko, W shouldn’t carry out the tempting kill - his only hope is letting the game stop with the outside ko open in W’s favor. There are some tricky L/D and seki issues then.


“If B stops fighting for the outside ko, W (with his outside liberty) can”
connect an internal ko, since this results in Black being dead in double-ko.
(though your one-point-worse comment still applies)

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I’m not sure it’s dead in double ko in the sense that’s used in the life and death phase.


Something like this would be dead in double ko, or black alive in double ko.

But here after black connects the outside ko, white is going to have to remove the inside black stones from the board.

(I went back a couple of moves, having black pass leaving the outside ko open)

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