Philidor position

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This article uses algebraic notation to describe chess moves.

Philidor's position usually refers to an important chess endgame which illustrates a drawing technique when the defender has a king and rook versus a king, rook, and pawn. It is also known as the third rank defense, because of the importance of the rook on the third rank cutting off the opposing king. It was analyzed by Philidor in 1777. (Also see rook and pawn versus rook.) Philidor analyzed many positions, some of which have his name associated with them (see the subsequent sections).

Contents 1 Philidor's position, rook and pawn versus rook 2 Queen versus rook 3 Rook and bishop versus rook 4 See also 5 Notes 6 References 7 Further reading

[edit] Philidor's position, rook and pawn versus rook

The diagram shows an example of Philidor's position. The important characteristics of the position are (from the point of view of the defender):

• the defending king (White in this diagram) is on the queening square of the pawn (or adjacent to it). The pawn can be on any file.
• the opposing pawn has not yet reached the defender's third rank (its sixth rank).
• the opposing king is beyond the defender's third rank.
• the defender's rook is on the third rank, keeping the opposing king off that rank.

Black would like to get his king to the e3 square and threaten checkmate to force the white king away from the queening square of the pawn, e1. The white rook on the third rank prevents that. If Black checks with the rook from the side, White simply keeps the king in front of the pawn by alternating between squares e1 and e2. If Black offers an exchange of rooks White should take it, since the resulting king and pawn endgame is drawn (see King and pawn versus king).

So Black's only chance of progress is to advance the pawn. The basic idea is for the defender to keep his rook on his third rank until the pawn advances to that rank, then check the opposing king from behind. Here is a possible continuation:

1. ... Rb2

2. Rc3 Ra2

3. Rb3 e3

Black plans to move Kf3, then if he is unopposed, checkmate with the rook or advance the pawn. (A passive defense does not work.)

4. Rb8!

Since now Black's king can not move to e3, it is safe to move the rook away to the far end of the board (the defender's seventh or eighth rank).

4. ... Kf3

5. Rf8+ Ke4

6. Re8+

The black king can not hide from the checks without giving up the pawn; nor can he approach the rook:

6. ... Kf4

7. Rf8+ Ke5

8. Re8+

The defender's rook must be on his seventh or eighth rank for this defense to work.

To sum up the defense: the defender should keep his king in front of the opposing pawn and keep his rook on the third rank until the pawn advances to that rank, then go to the far end of the board (the seventh or eighth rank) and check the king from behind. If the attacker tries to get his king to his sixth rank by moving his rook to that rank first to block the checks, the defender simply exchanges rooks and has a drawn king and pawn versus king endgame.

Philidor actually studied a position that leads to the type of position above. In this position, if it is Black's turn to move, he moves

1. ... Rb4

and then his rook will reach his third rank, and the position is basically the same as the diagram above, with colors reversed. If White is to move, he wins with accurate play by

1. Ke6 Kf8 (2. Ra8# is threatened, moving the king to the "short side" of the pawn is relatively better than to the other side)

2. Ra8+ Kg7

3. Kd6 Rd4+

4. Ke7 Rb4

5. e6

etc, and wins (Nunn 1999:281-82).

Philidor's defense can also be used if the pawn is less advanced. In that case, the black rook can occupy its fourth rank instead of its third rank and the black king should be on at least its second rank. When the pawn reaches the rank of the black rook, the rook moves to its eighth rank to check the white king from behind (assuming that the opposing rook isn't on that rank) (Howell 1997:42).

[edit] Queen versus rook

Philidor studied many endgame positions. Another one that he studied in 1777 (and is also called Philidor's Position) involves a queen versus a rook (see the diagram).

If Black is to move in this position, he quickly loses his rook by a fork (or gets checkmated). For example,

1. ... Rb1

2. Qd8+ Ka7

3. Qd4+ Ka8

4. Qh8+ Ka7

5. Qh7+

If White is to move in this position, he would like to be in this position except with Black to move. This can be accomplished by triangulation:

1. Qe5+ Ka8

2. Qa1+ Kb8

3. Qa5

and now it is back to the same position but Black has to move (and is in Zugzwang) (Nunn 2002:50-51). Nunn describes that with the pieces in the centre of the board the queen ought force the rook towards the philador position. Nunn describes the various retreat positions for the rook, the "fourth, third, second" rank defences, then the "philidor position". Checkmate is possible inside fifty moves.

[edit] Rook and bishop versus rook

Another famous position studied by and named after Philidor is in the ending of a rook and bishop versus a rook (diagram). White wins because his king has reached the sixth rank and black's king is poorly placed (opposite the white king) (Howell 1997:148-50).

Interestingly, many of the longest games on record involve this endgame ^[1].

[edit] See also

• Rook and pawn versus rook
• Lucena position
• Endgame

[edit] Notes

[edit] References

•  James Howell (1997). Essential Chess Endings: The tournament player's guide. Batsford. ISBN 0-7134-8189-7. 

•  John Nunn (1992, 1999). Secrets of Rook Endings. Gambit Publications. ISBN 1-901983-18-8. 

•  John Nunn (1994, 2002). Secrets of Pawnless Endings. Gambit Publications. ISBN 1-901983-65-X. 

[edit] Further reading

• John Emms (1999). The Survival Guide to Rook Endings. Everyman Chess. ISBN 1-85744-235-0. 

•   Reuben Fine and Pal Benko (1941, 2003). Basic Chess Endings. McKay. ISBN 0-8129-3493-8. 

•   Victor Korchnoi (1999, 2002). Practical Rook Endings. Olms. ISBN 3-283-00401-3. 

• Minev, Nikolay (2004), A Practical Guide to Rook Endgames, Russell Enerprises, ISBN 1-888690-22-4

•   Karsten Müller and Frank Lamprecht (2001). Fundamental Chess Endings. Gambit Publications. ISBN 1-901983-53-6. 

•   Chris Ward (2004). Starting Out: Rook Endgames. Everyman Chess. ISBN 1-85744-374-8.