[Welcome to Sensei's Library!]

StartingPoints
ReferenceSection
About


Referenced by
ThePracticalEndga...
EndgameTestOneSol...
EndgameTestOneSol...

 

Endgame Test One - Solution 3
  Difficulty: Dan level   Keywords: Problem, EndGame

More analysis of "The Practical Endgame Test One".

Solution is White wins by 4 points - find it at Endgame Test One Solution.


[Diagram]
Diag.: Can B keep the margin to 3?

When Arno posted this position, I became fascinated by the question can Black force a better result than W+4? It took me a long time to think that I found the answer... --DaveSigaty



[Diagram]
Diag.: Variation 1

Black plays 1 because otherwise White's play at b is too damaging. White then goes back to 2, giving Black the chance to capture at 3. If White now plays on the left, Black plays 5 forcing 6. White can not ignore 5 because Black 6 followed by descending to the edge is a very big play (even bigger than capturing the two black stones if White plays at d instead of 6).

On the left side, Black at 7 is the right way to play. When White cuts at 4 it is worth 2 points for Black to ensure an eye on the left side. Otherwise he will have to play another stone on the right to prevent White's atari at c.


[Diagram]
Diag.: W+3

Black has two poins on the left and 10 points on the right.
White has four points at the bottom and 11 points at the top.
White wins by 3 points.

(NB: don't forget to count the captured stones.)



[Diagram]
Diag.: Variation 2

White can try blocking at 4 knowing that she can win a ko fight. However, Black does not need the ko to improve on the solution diagram...


[Diagram]
Diag.: Imperfect reversion

Now note that if White captures at a and connects, we have reverted to the solution diagram except that the marked white stone has been added inside White's territory. In addition each side has captured one stone near a but they offset each other. Final result? W+3.



[Diagram]
Diag.: Variation 3

White plays 2 after reading out that she can't let Black capture here. However, 3 is a big play with the follow-up at 5 as absolute sente. Play continues to 10 but White's winning margin has been reduced to a single point.



To summarize: if White plays the marked move in the first diagram Black can force a three point loss, instead of the four point loss in the correct solution.



This is a copy of the living page "Endgame Test One - Solution 3" at Sensei's Library.
(C) the Authors, published under the OpenContent License V1.0.