Beginner Exercise 45 / Solution

Sub-page of BeginnerExercise45

White first

[Diagram]
Solution  

The key move for White is to descend with W1. White lives unconditionally with 9 points, capturing Black stones.

[Diagram]
Solution  

If B2 blocks here, then W3 wins the race. Note that Black cannot approach at a.

If B2 at W3, then W3 at B2 captures the Black stones just as well.

[Diagram]
Inferior: seki  

The hane at W1 might be an instinctive move, but in this problem it is a mistake. Now B2 can make a throw-in, and Black gets an opportunity to play B4 White cannot approach at either a or b. The result is seki. (W3 is not immediately necessary. B4 is an endgame play worth 8 points in gote.)

[Diagram]
Failure: ko  

Starting a ko with W3 is a risky preposition - it puts the life of the entire White group at stake. In life-and-death problems, by convention ko for life is always treated as inferior to unconditional life - and rightly so.


Black first

[Diagram]
Solution  

Black can kill unconditionally with the descend, B1.

Unlike most other problems, the proverb the opponent's vital point is my vital point does not apply in this problem.

[Diagram]
Solution  

White just does not have the liberties needed anymore.

[Diagram]
Solution  

In this variation, White is still dead. White cannot play at a because of a shortage of liberties.

[Diagram]
Failure: seki  

Although White at B1 is the key for making unconditional life, Black playing at B1 here only results in a seki after W2 and W4. (Black's attempts at under the stones play all fail. see /BlackAttempts)



Beginner Exercise 45 / Solution last edited by hnishy on September 2, 2024 - 01:35
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