Beginner Exercise 266 / Solution

Sub-page of BeginnerExercise266

This page is in need of attention.
Reason: this problem is already not easy and the solution involves too many calculations to make it a beginner problem. Just living is fine in itself.


[Diagram]
Main Diagram  

First, let's try all the moves including tenuki.

[Diagram]
Tenuki doesn't work (W6 at white+circle)  

'e' in the Main Diagram is the same.

[Diagram]
'a' doesn't work  

After W4, it doesn't matter black captures with 'x' or 'y', white can throw in and black has no eye in the corner. If black plays B3 at W4, white plays 'x'.

[Diagram]
'c' doesn't work  
[Diagram]
'd' doesn't work  



Comparison

Two option left, let's see which one is better.

[Diagram]
'f' (B5 at white+circle)  

White probably wouldn't play W2 and W4 right away, but it's sente for white, so it's reasonable to assume white would get them. Ko threat wise, white has W2,W4, and 'm' before the end game. Points: 5 Ko threats: 3

[Diagram]
'b'  

Notice black has to capture with 'w' later, so it's one point less than it looks. Also, if we assume the outside is going to be white's territory, then it's another one point less than it looks. The reason is: black won't get all three of 'x','y', and 'z', because the last one is going to be gote for black and sente for white. Ko threat wise, there's another ko threat before the end game at 'n' besides W2. After that, there's another two-point losing threat at 'v'.

Points: 9-2 = 7 Ko threats: 2 + 1 two-point-losing threat

Verdict

[Diagram]
 

Only 'f' and 'b' saves black, and 'b' is the best. 'b' is about 2 points better.



Beginner Exercise 266 / Solution last edited by Dieter on July 29, 2014 - 11:06
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