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Two-by-three box
Path: BasicDeathShapes · Prev: ThreeInARow · Next: Path: LifeAndDeath · Prev: TwistedFourInTheCorner · Next: TwoByFourBox
Keywords: Life & Death
1. No outside liberties
If there are no outside liberties, White can kill Black unconditionally by playing at a.
After
Andrew Grant: No! Black is already dead after 3: for White to play a or the point to the left is a waste of a move.
2. One outside liberty
When there is exactly one outside liberty, the best White can do is to make it a rogue ko. The vital point is at a.
Black's throw in at
After the marked stone (Black a in the previous diagram), White sets up another ko with
With one outside liberty, this 3. Two or more outside liberties
When there are at least two outside liberties, Black is unconditionally alive.
The sequence is copied from the main line in the previous paragraph. Now Black can play the surprising move of AddendumIn this diagram, Black is dead. No, this is not a seki. Why?
After
If Footnote:
[1]: One could argue that, this being the case, White might as well fill the outside liberty in the main line diagram instead of connecting at Authors: WikiMasterEdited by Dieter. Original posts now at TwoByThreeBoxDiscussion. Path: BasicDeathShapes · Prev: ThreeInARow · Next: Path: LifeAndDeath · Prev: TwistedFourInTheCorner · Next: TwoByFourBox This is a copy of the living page "Two-by-three box" at Sensei's Library. ![]() |