Beginner Exercise 23 / Solution

Snapback on both sides  

In symmetrical positions, one useful proverb is to play on the point of symmetry. White cannot defend both snapbacks (without loss of generality the left side is defended) and thus the only real eye in the White group is the marked point - White dies a horrible death.

Not the point of symmetry  

here is incorrect. After , white is assured of the top and the bottom eye.

What about this for 3?  

timh?: Is this another option for following up on ? Then white needs both a and b to survive, so black takes the other one to kill.

Sufficient, but inferior  

From my reading, while it does also do the job, above gives W 3 ko threats to live in the future. (3rd threat is under the stones at the marked W stone).

Slightly better  

In the snapback solution, W only have 2 ko threat to live: the atari and the under-the-stones play. The creation of an eye at the top (at a or b) is no longer a threat to live.

White can live  

Anonymous: But couldn't White live by playing at ? If Black follows up with a, White captures both stones at b, and if Black follows with b, White plays a and lives.

Reuven: is self atari, B will capture the 3 stones now. If W then plays at b, trying to make an eye - will be played under , leaving it as a fake one.

Alternative Solution?  

Moosky: *I'm not the poster of the diagram*. As far as I can read, this works. that's why W played there in the original version of the problem.