Weekly Problems 2010

An incomplete block where 1…Kb2 2.Qxa2 is set, but no mate is available against 1…b3 initially. The key 1.Qe6! (waiting) yields a flight, 1…Kd3 2.0-0-0, provides for 1…b3 with 2.Qe2, and leaves 1…Kb2 2.Qxa2 unchanged.

Dennis Hale: I admire the simple elegance of this problem.
Cdr R. Ganapathi: The reply to 1…Kd3 2.0-0-0 is the icing.
Brian Stephenson: An uncharacteristically light position for this composer. 

Every possible black move has been provided with a set mate: 1…Sxf3 2.Sxf3, 1…Sxf4+ 2.Qxf4, and 1…Sg-else 2.Qe1. The waiting key, 1.Qh2!, keeps the 1…Sxf3 2.Sxf3 and 1…Sxf4+ 2.Qxf4 variations, but generates two new mates with 1…Se3 2.Rd3 and 1…Se1 2.Sc4, so this is a mutate.

Andy Sag: Key changes mates after 1…Se1 and 1…Se3. Tries 1.Qf2? Sxf4+!, 1.Bd3? (threat: 2.Sc4) b5!
Ian Shanahan: Nice mutate, if rather heavy.

The key 1.Kc8! is a sort of anticipatory self-pin of the d7-rook. The threat of 2.Rc7 is disabled by any black rook move, which pins the white piece by discovery. A random black rook move, 1…R~, allows 2.Qd4. Two correction moves by the rook prevent 2.Qd4 but they err by interfering with another black piece, 1…Rf4!? 2.Qc7, 1…Re4!? 2.Qxd5. The b2-knight also produces correction play: 1…Sa4 is the ‘random’ defence that permits 2.Qe2; 1…Sd3!? corrects by eliminating the queen mate but self-blocks, 2.Bb3. Also, 1…Bxe5 2.Sxe5, 1…d4 2.Qc5.

Brian Stephenson: The key, unpinning the white queen, is not of the best, but it does lead to four queen mates, and 1…Sd3 2.Bb3 is a nice addition.

After a waiting key, 1.Qa4!, the white queen has two potential mates on d7 and d1. Both are currently stopped by the black queen, which is focusing on the defensive squares d6 and d2. If Black moves the queen, the focus cannot be maintained and White exploits this accordingly, 1…Qg5 (or to f4, e3, etc.) 2.Qxd7, and 1…Qg6 (or to f6, e6, etc.) 2.Qd1. Some pawn defences lead to the same queen mates due to self-interference, 1…g6 2.Qxd7, 1…g5 or 1…e3 2.Qd1. A good variety of traditional play occurs in the remaining variations, 1…e6 2.Rd6, 1…d6 2.Sb6, 1…c3 2.Qxe4, 1…R-any 2.Sxe7, 1…S-any 2.Qxc4.

The key 1.Rxg3! threatens 2.Rxh3 and allows a check. The threat and ensuing seven variations generate mates from each of the eight ranks. 1…Rxg3+ 2.hxg3, 1…Rxh2 2.Rxh2, 1…Rh4 2.Qxh4, 1…Kh5 2.Qg5, 1…Sf3 2.Qxg6, 1…Rh5 2.Qg7, 1…Bxe6 2.Qh8.

A nice key 1.Qb2! gives a flight on c6 and threatens 2.Se7. When the black king takes the flight, White mates with a switchback: 1…Kxc6 2.Qb7. The well-utilised white queen delivers three more mates, 1…Sxc6 2.Qa2, 1…Sc8 2.Qb5, 1…e3 2.Qg2. Also, 1…Rxe6 2.Rc5.

Andy Sag: The key gives a flight capture and good variety of queen mates including a switchback.
Steven Sugg: Something elegant about moving your queen to threaten mate (and leave your rook unprotected) only to move her right back to her original square to secure mate!

The unprovided flight 1…Ke4 signals the solution somewhat – 1.Qe1! (waiting), which answers 1…Ke4 with the pin-mate 2.Qh1. The key is still good though, in that the queen abandons the Q + S battery while preparing to support the white pawn in the star variation, 1…B-any 2.e4. Two more lines are unchanged from the set play, 1…S-any 2.Bxc4, and 1…e4 2.Rg5.