[blind-chess] Chess Article #52: The Chess Endgame: The Philidor Position
- From: Roderick Macdonald <rmacd@xxxxxxxx>
- To: Blind Chess Mailing List <blind-chess@xxxxxxxxxxxxx>
- Date: Mon, 14 Jun 2010 19:25:11 -1000 (HST)
Chess Article #52
The Chess Endgame: The Philidor position
Adapted and Condensed from
Wikipedia, the Free Encyclopedia
The Philidor position (or 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 Francois-Andre Danican Philidor in 1777. (Also see rook
and pawn versus rook endgame.) Most rook and pawn versus rook
endgames reach either the Philidor Position or the Lucena Position
if played accurately. The Philidor position is perhaps the most
important position in endgame theory (de la Villa 2008:125).
Philidor analyzed many positions, some of which have his name
associated with them (see the subsequent sections).
Philidor's position, rook and pawn versus rook
Diagram 1: Philidor position, 1777
White: King at e1 rook at a3
Black: King at f4, rook at h2 Pawn at e4
White is defending the Philidor position, and draws.
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 endgame).
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). Note that 4.Rb4+ (??) loses immediately to 4...Kf3
when black will checkmate or force the exchange of rooks followed
by Kf2 and promotion of the pawn.
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.
Diagram 2: Philidor, 1777
White: King at d5, rook at 17, Pawn at e5
Black: King at e8, Rook at f4
White to move wins; Black to move draws.
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).
Queen versus rook
Diagram #2: Philidor, 1777
White: King at c6, Queen at a5
Black: King at b8, rook at b7
White wins with either side to move
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 #2).
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), (M`uller & Pajeken 2008:178).
Nunn describes that with the pieces in the center of the board the
queen ought to force the rook towards the Philidor position. Nunn
describes the various retreat positions for the rook, the "fourth,
third, second" rank defenses, then the "Philidor position". The
rook can be won in fewer than fifty moves, avoiding a draw by the
fifty-move rule.
Rook and bishop versus rook
Diagram 3: Philidor, 1749
White: King at d6, Rook at f7, Bishop at d5
Black: King at d8, Rook at e2
White to move wins.
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). If
this type of position arises, it is usually because of inferior
defense. Nevertheless, it is tricky to win (Nunn 2007:163).
The winning method is as follows:
1. Rf8+! Re8
2. Rf7!
threatening to switch to the other side and checkmate.
2. ... Re2
If 2. ... Re3 3. Rb7. If now 3. ...K c8 4. Ra7 and checkmate on a8,
else black loses the rook because the bishop covers b3 (one of the
reasons white wants to force the black rook to the third rank). If
3. ... Rc3 5. Rd7+ and white has achieved the position at move 8
below, only some moves faster. Other second moves for black lose
faster: 2. ... Rh8. 3. Ra7 Rh6+ 4. Be6 with checkmate or loss of
rook. 2. ...K c8 3. Ra7 Rd8+ 4. Kc6 Kb8 5. Rb7+ Ka8 (5. ... Kc8 6.
Be6+) 6. Rb1 Ka7 (6. ... Rc8+ 7. Kd7+) 7. Kc7 with checkmate or
loss of rook to follow. Correct bishop moves are required for White
to win.
3. Rh7 Re1
4. Rb7
The winning line only works if the white rook is on b7 or f7.
4. ... Rc1
Or 4. ... Kc8 5. Ra7 Rb1 6. Rf7 Kb8 7. Rf8+ Ka7 8. Ra8+. White wins
because the chessboard has only eight files.
5. Bb3
This is the key idea. It forces the black rook to the inferior
third rank while preventing 5. ... Rd1+. Black is in zugzwang.
5. ... Rc3
If instead 5. ... Kc8 then 6. Rb4 Kd8 7. Rf4 Re1 (or 7. ... Kc8 8.
Bd5 Kb8 9. Ra4) 8. Ba4 Kc8 9. Bc6 Rd1+ 10. Bd5 Kb8 11. Ra4. Now
White completes the following maneuvers, getting the bishop back to
d5 with gain of tempo.
6. Be6 Rd3+
7. Bd5! Rc3
8. Rd7+ Kc8
If 8. ... Ke8 then 9. Rg7 and checkmate on g8 next move, else loss
of rook since the bishop covers f3.
9. Rh7 Kb8
10. Rb7+ Kc8
11. Rb4 Kd8
If 11. ... Rd3 12. Ra4 and checkmate or loss of rook since the
bishop covers b3.
12. Bc4
Stopping the check on d3 and cutting off the rook entirely.
12. ... Kc8
13. Be6+ Kd8
14. Rb8+
and checkmate next move (Howell 1997:148-50), (Nunn 2007:163-64),
(M`uller & Pajeken 2008:178).
This is an exercise in domination of the king. Many of the longest
games on record involve this endgame, especially during the period
when the fifty move rule was extended to 75 or 100 moves for this
combination of material.
==========
The blind-chess mailing list
View list information and change your settings: //www.freelists.org/list/blind-chess
List archives: //www.freelists.org/archives/blind-chess
=========
Other related posts:
- » [blind-chess] Chess Article #52: The Chess Endgame: The Philidor Position - Roderick Macdonald
