Last week‘s puzzle was a Mate in 3:

White has to choose the correct way to release the stalemate, which is…

1. Rb1

Black must reply:

1… Kg7
2. Qb7+

Now Black has four choices, north east, north west, south east or south west (problemists call these star flights):

2… Kf8
3. h8Q/R#

2… Kh6
3. h8Q/R#

2… Kf6
3. Rb6#

2… Kh8
3. Qb2#

This last variation explains why White had to choose Rb1 on move 1. This is a Bristol clearance: the rook has to clear the b-file for the queen to travel in the same direction.

It’s White’s move. Your answers, please! I need full analysis, not just one move!