Endgame Problem 9 / Solution

Sub-page of EndgameProblem9

The informal analysis


W1 is the solution, not a.


What is so painful for Black is that W5 is practically a sente move during the endgame phase. After B6, then White can tenuki, so White has reduced Black's territory in sente.


B2 does not work either. Black loses even more this way.


W1 is considered a failure in this problem. After B4, if White saves the two stones at a, then it is gote. Nothing more than an itch for Black.

The more formal analysis

Almost sente  

Bill: W1 - W3 is fairly large, about 8.7 points.

Large gote  

W10 connects at black+circle.

B1 is almost as large, about 8.4 (8.5 points when White is komaster). So White will often be able to play here with sente.

Later B5 - W6 is sente, and even later B9 - W10 is sente.

The count in this end position is -1 for the captured stone. White at B9 would forestall 2 points and then create a ko to capture first in sente. So B9 is a 2 1/3 sente. White at B5 would forestall 3 points (and no more if Black is komaster), so B5 is a 3 point sente

Large gote  

Here the count is 8


Game tree

            3.5 (4.5)
          /   \
         8   -1 (3)
             / \
 (-2 -1/3) -1  -4
           / \
         -1  -3 -1/3

Endgame Problem 9 / Solution last edited by Dieter on June 20, 2023 - 18:10
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