![]() StartingPoints Paths
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Two by four box
Path: LifeAndDeath · Prev: TwoByThreeBox · Next: WalkieTalkieSeven
Keywords: Life & Death
1. No outside liberties
If there are no outside liberties, White can make a sente seki.
White 1 is the strongest attack. Black 2 is the vital point. Black 6 is necessary or White plays there (or to the right of it) to capture the corner.
If Black 4 here, White 5 makes a thousand year ko. This result is generally worse for Black than a seki.
Black 2 at the 2-2 point invites another thousand year ko.
White 5 in this variation spoils the chance of a ko and invites a seki. 2. Outside liberties
If there is at least one outside liberty, Black is alive with 7 points.
Now Black 2 and the throw in at 4 work. Black 6 creates damezumari for White. If there were no outside liberty, Black 6 would put himself in atari. Conclusion for the endgame
White 1 threatens to destroy 7 points in sente (assuming capturing the corner would decide the game). Black 2 makes 7 points in reverse sente. So, White 1 is a typical ko-threat but if so, it is a bad one. In case of a ko the previous diagram supplies 4 ko-threats, that's one more than here. Path: LifeAndDeath · Prev: TwoByThreeBox · Next: WalkieTalkieSeven This is a copy of the living page "Two by four box" at Sensei's Library. ![]() |