TsumegoFromGames101/ Solution

Miai  

Chris Hayashida: makes one eye in the upper left corner. At this point, a and b become miai for a second eye.

After reading the discussion below, it sounds more like b and c are miai for the second eye. c is the vital point for the first L+1 group.

Alive  

Chris Hayashida: First, the easy case. If , then makes a second eye.

Alive, but White might lose two stones  

If Black plays instead, then it's more complicated. White ataris at , forcing . After that, White has the first L+1 group. White plays to make life.

Dead  

If White tries to save the two stones, Black plays . White is left with a dead L group. It would have been better to sacrifice the two marked stones so that the whole group doesn't die.

Miai  

Zook: I think this is an interesting variation too. At first sight, it looks as if a and b are miai to kill the outer eye and White is still left with a L-group in the corner. However, there are weaknesses in Black's position.

L-group  

White now opens one of the variations in the L-group to make use of the weakness at the circled point.

someone: Question: what if at ? Zook: See ^[1].

Life  

captures two stones. If Black throws in, White captures his stones by pushing through at .

Bent four, but enough liberties  

Zook: If here (instead of two diagrams earlier above), this is basically a variation discussed at bent four in the corner (check that page). White has enough outside liberties to avoid the ko.

The problem  

Zook: If at , I suddenly find a problem. Still thinking ...

Chris Hayashida: I updated this diagram to show Zook's problem. and falsify White's second eye. and can be swapped, and the eye is still false.

Miai  

Yeah, White has to start at here after exchanging the alleged marked miai!

Miai  

Chris Hayashida: What if Black plays at the critical point? White cannot immediate play at b. makes a and b become miai for life.