GokyoShumyoSection2Problem27/Attempts

The circled stone is of no concern.  

jms: I think we can safely ignore the stone. If is played at , it is gote for black (and a mistake, as the move is uneccesary).

Instead, if black plays at 'a', is still fine. Could B play at b to threaten an eye?

Solution?  

jms: There are many possible continuations - but I think B has no eyespace after

Carpenter's square  

The difference is that White can make an extra move now, while Black has a free hane at a and a leg at . Also note that Black has outside liberties which is a theme in the carpenter's square.

A systematic approach  

A systematic approach starts from here: an attempt to reduce the eyespace first. Black lives.

L+2  

This variant, playing Black's best answer before he can do so, leads to something similar to a L+2-group which is a much easier shape than the carpenter's square. a and b are miai.

Variation at  

The 1-2 points are miai too. White can now connect on the first line, or create a dead nakade thanks to the special properties of the corner.

Variation at  

If stretches, White kills with a placement and a hane . If Black continues with a, then b produces a bent four in the corner shape.

L+2  

unkx80: I'll assume that is Black's sente. Then after , White has to play at instead of a.