Is this the most bizarre mate-in-2?

Feb 13, 2015, 4:50 AM |

I came across this mate-in-2 in Polgar's book of 5334 chess problems (no. 634 since you ask). It has to be one of the most complex and surprising mate-in-2's I've ever seen:

The position is typical of many mate-in-2 problems in that the king cannot move, and you only need to deliver a check to finish him off. But, Be6+ fails to Bxe6, Rd6+ fails to Qxd6, Nc3+ fails to Rxc3 and c4 allows either Nxc4 or Ke4; so, how to deliver the final blow?
The analysis of why all mate-in-1's fail gives the answer; one of the defenders must be persuaded to move. This gives the surprising answer Qe4+!! - placing the queen on a square where it can be captured by no less than five of black's pieces. Yet any of these captures means black must give up one of the defences necessary to prevent checkmate, as the above puzzle shows.