BQM 374

Question  

TimK asks, in the solution main line of Kyu Exercise 75, whether is better played at a?

Solution 1  

Dieter thinks: is Black's sente. After , there remains a 1,5 gote.

Solution 2  

is sente. White has one point more, Black too. In the solution diagram 1, White is perhaps more likely to capture and cover the ko, so it is better by half a point. Now let the endgame beasts loose ...

Difference game, Black first  

Bill: If Black plays first, he wins.

Difference game, White first  

Bill: And if White plays first, she wins.

Bill: So which is better depends upon the rest of the board. (Note that the solid connection yields fewer ko threats.)

Another Black follow up  

Tapir: For Black can work as ko threat as well, if it does it is better than the hane in solution 1. It threatens a ko at a.