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28thMeijinGame5Li...

 

28th Meijin Game 5 Life and Death Problem Solution
    Keywords: Problem

[Diagram]
Miai

Chris Hayashida: W1 makes one eye in the upper left corner. At this point, a and b become miai for a second eye.

After reading the discussion below, it sounds more like b and c are miai for the second eye. c is the vital point for the first L+1 group.


[Diagram]
Alive

Chris Hayashida: First, the easy case. If B1, then W2 makes a second eye.


[Diagram]
Alive, but White might lose two stones

If Black plays B1 instead, then it's more complicated. White ataris at W2, forcing B3. After that, White has the first L+1 group. White plays W4 to make life.


[Diagram]
Dead

If White tries to save the two stones, Black plays B3. White is left with a dead L group. It would have been better to sacrifice the two marked stones so that the whole group doesn't die.



[Diagram]
Miai

Zook: I think this is an interesting variation too. At first sight, it looks as if a and b are miai to kill the outer eye and White is still left with a L-group in the corner. However, there are weaknesses in Black's position.


[Diagram]
L-group

White now opens one of the variations in the L-group to make use of the weakness at the circled point.

someone: Question: what if B6 at B8? Zook: See [1].


[Diagram]
Life

W1 captures two stones. If Black throws in, White captures his stones by pushing through at W3.


[1]

[Diagram]
Bent four, but enough liberties

Zook: If B1 here (instead of B6 two diagrams earlier above), this is basically a variation discussed at bent four in the corner (check that page). White has enough outside liberties to avoid the ko.


[Diagram]
The problem

Zook: If B3 at W4, I suddenly find a problem. Still thinking ...

Chris Hayashida: I updated this diagram to show Zook's problem. B3 and B5 falsify White's second eye. W4 and B5 can be swapped, and the eye is still false.


[Diagram]
Miai

Yeah, White has to start at W1 here after exchanging the alleged marked miai!



[Diagram]
Miai

Chris Hayashida: What if Black plays at B1 the critical point? White cannot immediate play at b. W2 makes a and b become miai for life.



This is a copy of the living page "28th Meijin Game 5 Life and Death Problem Solution" at Sensei's Library.
(OC) 2004 the Authors, published under the OpenContent License V1.0.