The Problem Corner #5
Problem #5 is a position composed by Hans Moravec. It's White to move and win. Have fun solving it!
White to move and win.
1. bxc7? Kxc7 is a theoretical draw, and after 1. b7? Kc6, White can make no further progress. Instead 1. Rd8+! Kxd8 2. b7 forces a queen.
Or does it? Black has a tactical resource too: 2. ... Rb4! 3. Kxb4 c5+! (diagram).
Now 4 Kxc5? Kc7 draws, because a king and rook-pawn cannot defeat a king that is anywhere near the queening square. Play might continue 5. Kb5 Kxb7 6. a4 Ka8 7. a5 Kb8 8. a6 Ka8 9. Kb6 Kb8 10. a7+ Ka8 11. Ka6 stalemate.
To win, White plays 4. Kb5! Kc7 5. Ka6! Kb8 (5. ... c4 6. Ka7 c3 7. b8=Q+ queens first) 6. Kb6! c4 7. a4 c3 8. a5 c2 9. a6 c1=Q 10. a7++. Who needs a queen anyway?