TsumegoFromGames81/Solution

Sub-page of TsumegoFromGames81
[Diagram]
a is best, b also kills, c leads to ko.  

The problem is quite straightforward. White and black have an equal number of liberties, so white must win the capturing race.

a is the best move. b also works, but is slightly worse for endgame purposes. c looks good, but allows black to make ko.


Table of contents Table of diagrams
''a'' is best, ''b'' also kills, ''c'' leads to ko.
Normal play.
Resistance by making an eye
Resistance by blocking
Slightly sub-optimal
W1 allows black to make ko.

Solution

[Diagram]
Normal play.  

This is the normal way to play the situation. W5 takes the stones, and white can still play a in the endgame


Resistance by black

[Diagram]
Resistance by making an eye  

If black tries to resist by making an eye with B2, white will still win the capturing race after W5.

[Diagram]
Resistance by blocking  

If black blocks at B2, white can simply connect at W3. The atari at a is oiotoshi (If black defends, white captures at b). If black plays a, we are back to a situation from the previous diagram, with moves B2 and B4 reversed.


Sub-optimal solution

[Diagram]
Slightly sub-optimal  

Although W1 also works, it is not as good as playing at W3 directly. When we compare this result with the correct solution, white has an extra move at W1, black an extra one at B6. So by playing W1, white has lost the endgame move at B6.


Allowing Ko

[Diagram]
W1 allows black to make ko.  

Although W1 looks good at first glance, B2 and B4 allow black to salvage a ko.

tderz W1 here, only can make sense in those situations where the white group lacks more liberties around 't' or white white+circle would be a black stone.



TsumegoFromGames81/Solution last edited by tapir on January 18, 2008 - 01:09
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