Tuesday, December 25, 2007

Philidor Gone Awry

I was working on a rook endgame position, specifically GM-RAM #50, and discovered that I really didn't know very much about rook endgames. Here is the position.

Black to move and draw.

This position is not technically a Philidor rook draw, but it is perhaps a cousin. Black should have his rook at a6, preventing the king and pawn from getting to the sixth rank. The solution to Black obtaining a draw is 1...Re1! Black allows White to kick his king around to f7, where it will cooperate with the rook to blockade e6. 2.e6 [ 2.Ke6 Kf8 3.Rh8+ Kg7 4.Ra8 Re2 ( 4...Rb1 5.Ke7 Rb7+! 6.Kd6 Rb6+!) 5.Kd6 Kf7! 6.Ra7+ Ke8 7.Ke6 Kf8=] 2...Rd1+= A regular Philidor position. Black will unceasingly harass White's King unless it gets too close in which case it will go back to e1 to harass White's pawn.

The interesting stuff came when I made Black miss the first move. What if Black tries to use the long side defense with 1...Ra1??

White to move and win.

Black has pinned his hopes on checking the White King laterally with a sufficient three-square distance from the pawn so that the White King will get caught out of position if it tries to approach the rook. However, White has a forcing variation that wins clearly.
White checks twice (like Santa) and moves into a queening position. 2.Rh8+! Kf7 3.e6+! Kf6 (3...Kg7 4.e7! Ra6+ 5.Kc5+-) 4.Rf8+ Kg7 5.e7+-.

If Black checks at g6, White gets the King and Pawn both on the 6th rank, threatening checkmate. 1...Rg6+??

White to move and win.

Creating mating threats against your own king is hardly ever advisable. 2.e6 Kf8 3.Kd7 Kg8 4.Rh1 Rg2 5.Rd1 Re2 6.e7 Kf7 7.Rf1+ Kg7 8.e8Q+-

1...Rd1+?? opened my eyes to my ignorance.

White to move and win.

I know that White should play 2.Ke6! so that the king hides behind its pawn and threatens checkmate. 2...Kf8 But how many of you know the next move after this?

White to move and win.

White plays two rook moves in a row, with the first designed to get the Black King to commit. 3.Rf7+!! Black must now choose between Kg8 and Ke8.


White to move and win.

4.Ra7! Kd8 5.Ra8+! Kc7 6.Ke7 Rd7+ 7.Ke8 Rd1 8.e6 Rh1 9.Ra7+ Kd6 10.e7 Rh8+ 11.Kf7 Rh7+ 12.Kf6 Rh8 13.Kg7 Rb8 14.Kf7 Rh8 15.e8Q+-

3...Kg8 Here's another move that might be hard to find.

White to move and win.

4.Rd7!! ( 4.Rc7?! doesn't lose the win, but it's a looping detour that must return through Rd7. 4...Kf8 5.Rf7+ ( 5.Rc8+ Kg7 6.Rc7+ Kf8 7.Rf7+)) 4...Re1 bringing us to one last diagram.

White to move and win.

5.Kf6! Two more times in this line, White's King makes a triangulation maneuver. Rf1+ 6.Ke7! Ra1 7.Rd2 Rd3 and Rd4 are also okay. 7...Ra7+ 8.Kf6! Rf7+ 9.Ke6! Triangle #2 Rf1 10.Ra2! Kg7 11.Ra7+! Kf8 12.Ra8+! Kg7 13.Kd6 Rd1+ (13...Kg6 14.e6 Rd1+ 15.Ke7 Rh1 16.Ra2 Rh7+ 17.Kd8 Rh8+ 18.Kd7) 14.Ke7! Triangle #3 Rb1 15.e6 Rb7+ 16.Kd6 Rb6+ 17.Kd7 Rb7+ 18.Kc6 Re7 (18...Rb1 19.e7+-) 19.Kd6! Rb7 20.e7 Rb6+ White can chase the Black rook now and when the checks run out, e8Q wins.

1 comment:

Wahrheit said...

Great stuff, thanks for laying it out--I thought memorizing the Philidor position was it :) but I can see I need to move up a level and know what to do when the Phil is unachievable.