Seki with eyes question 6
Yet another interesting seki with eyes:
This is a seki too, even though White can capture the two Black stones in the corner (but does not benefit from doing so!).
-- jvt
Why would this be a seki? White plays the 2-2 point, and can then play the 1-1 point to make 2 eyes. Something must be missing here.
-- bp
Using Chinese rules:
Black: 1 point, White: 2 points.
Using Japanese rules:
Black: 0 points, White: 0 points.
If White plays , Black will throw in with
. White can only capture the two stones with
and allow Black to capture two stones with
.
Using Chinese rules:
Black: 4 points, White: 4 points.
Using Japanese rules:
Black: 2 points, White: 2 points.
Using either ruleset, White does not gain by playing at the 2-2 point.
--unkx80
Bill: Under Japanese '89 rules, if this position remains at the end of the game, Black's two stones are considered to be alive, even though White to play can capture them. The following is not real play, which has ended. Rather it is a demonstration.
After the play is over, White claims that the stones are dead. And indeed, she can capture them with
-
. However:
jvt: This is taken straight out of Life-and-Death example 2 in the Japanese Rules 1989.
The two Black stones are alive: if White captures Black's two stones, Black can play two new stones (at and
) which White cannot capture. Since there is a dame, the position is a seki.
Bill: Jean-Pierre's point, which had originally slipped my mind, is that the capture of the stones allows new living stones (
and
) to be played. Therefore, at the end of play, the
stones are considered to be alive.
It sounds peculiar, but the Japanese '89 rules for post-play demonstrations provide a logical basis for most of the special rulings of the Japanese '49 rules.
jwaytogo: It should be noted that playing at the 2-2 point does not always result in a loss of points, and one should look at the specific situation and the specific ruleset. Below are some examples of similar situations. Sometimes, playing at the 2-2 results in a loss for white, sometimes in a gain. Can you figure out what happens in each of the following? (Hint: think under the stones)
If white stands to gain by playing at the 2-2 point, this also means there is value to black sacrificing a stone to ensure the seki remains.