Xuanxuan Qijing Problem 13 / Attempts

(1) Moves 1 to 5  

is the key move. Ko.

(2) Moves 1 to 7  

again Ko.

(3) continuation 1  

tderz: where is the ko here ?

(4) continuation 2  

tderz: this is ko about as Black cannot simply connect at as there there is the cutting point a.

(5) continuation 3  

tderz: Hence, as diagram (2) does not necessarily seem to end in ko (cf. proof diag. (3)),
and here is not necessary to create the eye e,
is not efficiently placed.

(6) continuation 4  

tderz: Only when changing the order like this,
Black seems to be forced to follow diagram (4).

(7) continuation 5  

Dave: It looks like White has to make Black decide how to reply before determining how to continue in the corner...

(8) continuation 5a  

Dave: If Black captures at , White can now play . If Black tries a hane ( or first), White throws in on the opposite side ( or White a) and gets a ko on one side or the other after ...

(8) continuation 5b  

Dave: If Black descends at , White forces with and then lives with since Black can not play at a due to shortage of liberties.

(8) continuation 5c ( connects)  

Dave: If Black continues on the right, then White is able to force Black on the left before living with .