Beginner Exercise 23 / Solution

Sub-page of BeginnerExercise23

Solution by lavalyn:

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  

B1 here is incorrect. After W2, white is assured of the top and the bottom eye.

What about this for 3?  

timh?: Is this another option for following up on B1? 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, B3 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 W2? If Black follows up with a, White captures both stones at b, and if Black follows with b, White plays a and lives.

Reuven: W2 is self atari, B will capture the 3 stones now. If W then plays at b, trying to make an eye - B3 will be played under W2, 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.

unkx80 But the original problem had a white stone at B1.

ajisubarashii: It's true that all of White's stones are dead after B1 in this diagram. However, if it was White's turn to move instead of Black's, White can do much better than playing at B1. Try the puzzle in the next diagram for extra practice.

unkx80: There are multiple initial moves that allow white to live. Which one(s) is/are the best?

White to play and live  

Beginner Exercise 23 / Solution last edited by on May 31, 2016 - 15:16
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