Beginner Exercise 140 / Attempts

Sub-page of BeginnerExercise140
Black to play.  

Taw: How about this ?

Hikaru79: This ends up extremely bad for black. White lives with either two prisoners in gote or one prisoner in sente.

unkx80: To Hikaru79: Actually, this is the sequence I am expecting. But the order of moves is wrong in this diagram.

Black to play.  

How about this?

unkx80: Both diagrams are wrong.

Malweth: My try

White has Ko to live  

unkx80: Good try, but unfortunately B1, B5 and W6 are wrong moves.

ChrisSchack: Next try, I guess. Of course, your comment about move order is a dead giveaway...

Black to play.  

This leads to ko, I think, and if B has enough threats. In place of W4, W can't simply connect at W1 as in the diagram below, else:

Continued - connect  

and now it IS a ko for life. Therefore, W would have to play so as indicated in the next diagram, in place of W4 above.

Continued - capture  

Which is quite the difference.

unkx80: Chris's solution is right, after I gave the hint and the comment. To being the discussion to a slightly higher level, I shall also mention the following in passing.


Without the black stone at a, W2 can extend and say arigato to Black for the free gift. Obviously White should not play W2 at b otherwise black can play at B2 and thank White instead.


On the other hand, with the marked stone, W2 is not good, as B3 starts a one step ko compared to a two step ko in the solution.


So without Black a, Black should atari at B1. The correct response is W2, irregardless whether there is a Black stone at a. I believe this is probably a IGS 1k* level indicator.

Beginner Exercise 140 / Attempts last edited by CharlesMatthews on November 2, 2003 - 20:31
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