Beginner Exercise 45 / Solution

Solution  

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

Solution  

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

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

Inferior: seki  

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

Failure: ko  

Starting a ko with 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

Solution  

Black can kill unconditionally with the descend, .

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

Solution  

White just does not have the liberties needed anymore.

Solution  

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

Failure: seki  

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