Beginner Exercise 73 / Solution

Solution  

, separating the eyespace into two, is the only way to live.

Proof 1  

White's invasion fails.

Proof 2  

Low invasion also fails.

Proof 3  

Simply blocked (Best for White.)

Failure  

Enlarging the eyespace make it a bulky five, so kills - a and b are miai for kill now. is exactly the point in the solution diagram.

Generally, expand the eyespace to the maximum and see how the opponent can kill - then apply the proverb "The enemy's key point is yours". This method often provide a good hint to find the solution, as in this exercize.