Kyu Exercise 151 / Solution

Solution  

The key move is . Its significance will be apparent in the failure diagrams.

Solution  

If blocks, then occupies the vital point and turns the bottom eye into a bulky five dead shape in sente. Note that Black cannot connect by capturing with .

Solution  

If defends this way, then moves in and kills.

Failure

Failure  

Directly occupying the vital point at allows to save half of his group. For the purpose of this problem, this result is considered a failure.

Notice that is the same point as of the solution, and threatens to connect out to the left side (as in this diagram) as well as to make a seki at the bottom side (see next diagram).

Failure  

Blocking with allows Black to save his entire group in a seki.

Failure  

The atari at is superfluous, allowing Black to live unconditionally. After , White cannot win the capturing race on the right side.

Failure  

If destroys the eye on the upper side, then takes the vital point and lives easily.