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.
The Solution:
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?



Comments
correct is
1.rd8+ kxr
2.b7 rb4
3.kxr c5+
4.kb5! kc7
5.ka6 kb8
6.kc6 c4
7.a4 c3
8.a5 c2
9.a6 c1(q)
10.a7 mate
Posted by: roger morin | April 30, 2010 3:08 PM
1.Rd8+Kxd8
2.b7c5
3.b8=Q+
The rook checking along the d file won't help, as eventually the king will get to a7 and the pawn will queen.
Posted by: Matthew | April 30, 2010 12:10 PM