[blind-chess] Chess Article #51: The chess Endgame: The Lucena Position
- From: Roderick Macdonald <rmacd@xxxxxxxx>
- To: Blind Chess Mailing List <blind-chess@xxxxxxxxxxxxx>
- Date: Sun, 13 Jun 2010 18:55:06 -1000 (HST)
Chess Article #51
The Chess Endgame: The Lucena position
Adapted and Condensed from
Wikipedia, the Free encyclopedia
Diagram:
White: King at b8, Rook at c1, Pawn at b7
Black: King at d8, rook at a2
The Lucena position, White wins
The Lucena position is one of the most famous and important
positions in chess endgame theory, where one side has a rook and a
pawn and the defender has a rook. It is fundamental in the rook and
pawn versus rook endgame. If the side with the pawn can reach this
type of position, he can forcibly win the game. Most rook and pawn
versus rook endgames reach either the Lucena Position or the
Philidor Position if played accurately (de la Villa 2008:125).
The position is incorrectly named after the Spaniard Luis Ramirez
de Lucena. The name "Lucena" is pronounced "Loo THAY na" (Shenk
2006:79) in Castilian Spanish.
Introduction
The so-called Lucena position is named after the Spaniard Luis
Ramirez de Lucena, although is something of a misnomer, because the
position does not in fact appear in his book on chess, Repeticisn
de Amores e Arte de Axedrez (1497). It does appear, however, in
Alessandro Salvio's Il Puttino (1634), a romance on the career of
the chess player Leonard da Cutri, and it is in that form that it
is given here (M`uller & Lamprecht 2001:179). Salvio attributes it
to Scipione Genovino (Hooper & Whyld 1992:238).
The position is shown above and below (it should be noted that the
position can be moved as a whole or mirrored so that the pawn is on
any of the files b through g). White's aim is to either promote his
pawn or else compel Black to give up his rook for it - either
result will leave White with an overwhelming material advantage and
a straightforward win. White has managed to advance his pawn to the
seventh rank, but it is prevented from queening because his own
king is in the way. White would like to move his king and then
promote his pawn, but is prevented from moving to the a-file by the
black rook, and prevented from moving to the c-file by the black
king.
The essential characteristics of the position are:
* the pawn is any pawn except a rook pawn
* the pawn has advanced to the seventh rank
* the attacking king (the one with the pawn) is on the queening
square of its pawn
* the attacking rook cuts off the opposing king from the pawn by
at least one file
* the defending rook is on the file on the other side of the
pawn
An obvious approach by White such as
1. Rd1+ Ke7
2. Kc7
gets nowhere. Black can simply harass the white king with checks,
and White makes no progress:
2. ... Rc2+
3. Kb6 Rb2+
4. Ka7 Ra2+
5. Kb8
The winning method: building a bridge
Diagram:
White: King at b8, Rook at c1, Pawn at b7
Black: King at d8, Rook at 12
The Lucena position, White wins
In the Lucena position, the side with the pawn has a winning method
that works for any pawn except a rook pawn (i.e. on the a- or h-
file). In some circumstances, it also works for a rook pawn.
In this position, White can win with
1. Rd1+ Ke7
2. Rd4!
Now, if Black plays a waiting move, such as 2. ... Ra1 hoping to
harass the white king with checks again as in the above variation,
White continues
3. Kc7 Rc1+
4. Kb6 Rb1+
5. Kc6 Rc1+
(or 5. Ka6 Ra1+)
6. Kb5 Rb1+
7. Rb4!
FEN: 8/
1P23/
8/
1K6/
1R6/
8/
8/
1r6/
Position after 7. Rb4! Black cannot prevent White from promoting
the pawn.
The black rook can no longer check the white king and Black cannot
prevent the pawn from queening (Ward 2004:48). White's shielding
his king and pawn with the rook in this way was described as
"building a bridge" by Aron Nimzowitsch (Hooper & Whyld 1992:238).
It is important that the white rook go initially to the fourth rank
if Black uses his most active defense: repeatedly checking the
white king. If Black abandons this defense, the white rook can
build a bridge on the fifth rank. In the line above, after
5. Kc6
if Black moves
5. ... Ke6
there is a trap for White: if 6. Rd5?? (to build a bridge on the
fifth rank) then 6. ... Rxb7! draws. However, if
6. Rd6+ Ke7
7. Rd5!
and White can build a bridge on the fifth rank by getting the rook
to b5, the king to b6, and then the pawn can promote (Ward
2004:48-49) (position reflected):
7. ... Rc1+
8. Kb6 Rb1+
9. Rb5
and White wins.
Black to move
from Emms
white: King at h7, rook at d5, Pawn at b7
Black: King at e7, Rook at b2
Position after 6. Rd5
If Black is to move in the diagramed position, he can prevent the
white rook from going to the fourth rank, but then White still
wins:
6. ... Ra4
7. Rd1+ Ke7
8. Kc7 Rc4+
9. Kb6 Rb4+
10. Ka6 Rb2
(The black rook is not far enough away to keep checking: if 10. ...
Ra4+ then 11. Kb5 wins.) Now White wins by blocking the checks with
11. Rd5
followed by
12. Rb5
(Emms 2008:17) (position reflected).
Bridge on the fifth rank
Diagram:
White: King at d8, Rook at f1 Pawn at d7
Black: King at g7, Rook at c2
from de la Villa
White to move makes a bridge on the fifth rank instead of the
fourth rank.
A bridge can also be built on the fifth rank (but it is better to
build one on the fourth rank). The main line goes:
1. Rf5
(instead of 1. Rf4!)
1. ... Rc1
2. Ke7
threatening to promote the pawn, Black can just delay it with
checks
2. ... Re1+
3. Kd6 Rd1+
4. Rd5
and the pawn will promote. Or
1. ... Kg6
2. Ke7?!
(better is 2. Rf8 Kg7 3. Rf4!, back to a bridge on the fourth rank)
2. ... Kxf5!
3. d8=Q
and White has a winning (but difficult) queen versus rook endgame
(see pawnless chess endgames) (de la Villa 2008:126-27).
Alternate plan for the defense
Alternative approaches are no better for Black. After 1. Rd1+ Ke7
2. Rd4 above, after
2. ... Rb2
for example, White can still carry out his plan as above, or he can
win with the simple
3. Ra4 Kd7
4. Ka8
(or 4.Ka7) Kc7
5. Rc4+
chases the black king away and allows the pawn to promote (or 5.
b8=Q Rxb8 6. Rc4+ wins the rook).
Rook pawn
Silman, diagram 223
White: King at a8, rook at e1, Pawn at a7
Black: King at f7, Rook at b2
White wins
The Lucena method also works with a rook pawn if the white rook is
already on the fourth rank, the black rook isn't on the file
adjacent to the pawn, and White is to move.
Otherwise, the defending king must be cut off four files from the
pawn, as in the diagram. This is not a true Lucena position since
the king is cut off by more than one file. White wins:
1. Rc1 Ke7
2. Rc8 Kd6!
3. Rb8 Ra2
4. Kb7 Rb2+
5. Kc8 Rc2+
6. Kd8 Rh2!
7. Rb6+ Kc5
8. Rc6+! Kxc6
9. a8=Q+
and White has a won queen versus rook endgame - one that is easier
to win than one where the rook is close to its king (Silman
2007:223-26).
Similar positions may be drawn
de la Villa, position 10.4
White: King at e8, Rook at f1, Pawn at e7
Black: King at g7, Rook at a2
Black to move draws
Not all similar positions are wins. In this position, Black draws
because he can safely check from the side. For this defense to
work, there must be at least three files between the defending rook
and the attacking king and the defending king must be so that it
doesn't block the checks. That is, the defending king is on the
"short side" of the pawn (the one with fewer files between the pawn
and the edge of the board) (de la Villa 2008:127-28). (See the
"short side defense" at rook and pawn versus rook endgame for more
details.)
Conclusion
There is an alternate method for winning this type of position that
works only for pawns on the c-file through the f-file, see Rook and
pawn versus rook endgame.
Rook and pawn endgames occur quite often in chess, about eight to
ten percent of all games (de la Villa 2008:18), (Emms 2008:6). This
position is very important since endgames may simplify to it. As it
is a known win, endgames sometimes revolve around the player with
the pawn trying to reach the Lucena position and the other player
trying to prevent it.
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