Monday, September 24, 2007

Lucena, not so simple?

Lucena is the most important position in Rook & Pawn vs Rook endings, so why do most books use only one or two diagrams to explain it?


Let's begin with a quiz. White to move. If you had the White pieces, which of the above positions could you win over the board?

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You should win them all. If that surprises you, read this Lucena lesson.

You win Rook & Pawn vs Rook if your pawn is on the 7th rank, your king is in front of it, and you have the move. Rook pawns are exceptions.


Let's try another quiz. Black to move. If you had the White pieces, which of the above positions could you win over the board?

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Draw. Black can draw by checking the White king from the side. 1...Ra8+! 2.Kd7 Ra7+! 3.Kd6 Ra6+! 4.Kc5 Re6 =.



Win! The Black king is misplaced on the eighth rank. 1...Ra8+ 2.Kd7 Ra7+ 3.Kd6 Ra6+ 4.Kc5 Re6 5.Rf8+! Kg7 6.e8=Q Rxe8 7.Rxe8 1-0.



Win! The Black rook is misplaced on the b-file. 1...Rb8+ 2.Kd7 Rb7+ 3.Kd6 Rb6+ 4.Kc7 Re6 Kd7 1-0. The rook requires three squares of checking distance, and in this case it only has two... a fatal problem.

If Black realizes that flank checks won't work, he may try a more sophisticated defense. 1...Rb8+ 2.Kd7 Rb7+ 3.Kd6 Rb8 4.Kc7 Ra8 5.Ra2!! Rxa2 6.e8=Q +/-. Now White needs to win a Queen vs Rook ending.



Win! But, you couldn't prove it over the board, so "Draw" gets the credit. As proof, 13 out of 14 top titled players failed to solve it within an hour.

This is a great illustration of how complex such endings can be. If you're curious about the solution, read about it at The Chess Mind.

Generally, you win Rook & Pawn vs Rook if your pawn is on the 7th rank and your king is in front of it, even without the move. Rook pawns are exceptions.

I hope this helped you learn more about Lucena.  :)

7 comments:

Joshua said...

Nice explanation of the Lucena position! I actually made a video explaining how to win the Lucena position. If you have time to check it out, please let me know what you think!

likesforests said...

Hi Joshua, I saw your video a couple days ago and it's also an excellent 5-minute explanation of the position. I recommend that readers check it out when they have time!

Blue Devil Knight said...

Awesome! You should make podcasts likeforests. I could take them on my plane trips. :)

likesforests said...

Podcasts? That sounds fun. But could anyone follow an all-audio stream where I'm saying "White rook on a1, king on e7, pawn on e6. Black rook on b2, king on g7... Ra7 check exclamation point, Kd6, Ra6 check..." :)

Anonymous said...

Really really nice site :)
I'll be a regular visitor for sure!

Anonymous said...

In the position with white king on e8, black king on g8, white rook on f1, white pawn on e7, and black rook on a2, Black to play, you give 1... Ra8+ 2. Kd7 Ra7+ 3. Kd6 Ra6+ 4. Kc5?, but that allows 4... Ra8! and there is no longer a win (5. Kd6 Kg7). Better is 4. Ke5 Ra8 5. Kf6 Ra6+ 6. Kg5 Ra8 7. Kg6 Ra6+ 8. Rf6 Ra8 9. Re6 Re8 10. Re1 +-

Anonymous said...

White: Ke8, Rf2, Pe7 Black: Kg8, Ra3 in the line 1.... Ra8+ 2. Kd7 Ra7+ 3. Kd6 Ra6+ 4. Kc5 Ra8 5. Ra2! still wins (and 5. Kd6 Kg7 6. Ra2 wins but not as easily) 5... Ra2 6. e8=Q+ Kg7 7. Qe7+ Kh8 (else 8. Qe6+) 8. Qf8+ Kh7 9. Qf7+. 5.... Rb8 6. Kc7 Re8 7. Kd7 +- So, there is nothing wrong with 4. Kc5.