Rook and bishop versus rook endgame

The rook and bishop versus rook endgame is a chess endgame where one player has just a rook, bishop and king, and the other player has only a rook and king. It has been studied many times through the years. This combination of material is one of the most common pawnless chess endgames. It is generally a theoretical draw, but the rook and bishop have good winning chances in practice because the defense is difficult. Ulf Andersson won the position twice within a year, once against a grandmaster and once against a candidate grandmaster; and grandmaster Keith Arkell has won it 18 times out of 18 (Hawkins 2012:193).[1] In positions that have a forced win, up to 59 moves are required (Speelman, Tisdall & Wade 1993:382). Tony Kosten has seen the endgame many times in master games, with the stronger side almost always winning (Kosten 1987:11). Pal Benko called this the "headache ending" (Benko 2007:154).

Computer endgame tablebases show that 40.1% of the legal positions with this material are theoretical wins, but that includes many unnatural positions that are unlikely to occur in games. Edmar Mednis estimated that less than 4% of starting positions that occur in games are theoretical wins (Mednis 1996:80).


History

Philidor

In 1749 François-André Danican Philidor (1726–1795) published a position in which the superior side can force a win. Giambattista Lolli (1698–1769) studied a similar position with a forced win. On the other hand, there are several drawing techniques possible if a winning position such as the Philidor position has not been reached. The Cochrane Defense was discovered by John Cochrane (1798–1878), the Szén position was discovered by József Szén (1805–1857), and there is the second-rank defense. Other winning and drawing positions were studied by Tassilo von Heydebrand und der Lasa, Josef Kling and Kuiper, and André Chéron (Nunn 2002:178–86).

Many of the longest chess games on record involve this endgame since at one time the fifty-move rule under which a draw could be claimed after fifty moves with no capture was extended to one-hundred moves for this combination of material.[2] For example, the longest tournament game on record is a 269-move game by Ivan Nikolić and International Master Goran Arsović.[3] The last 103 moves had this material and the game ended in a draw.

Winning positions

Philidor position

This famous position was studied by and named after François-André Danican Philidor. White wins because his king has reached the sixth rank and the black 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).

Philidor, 1749

abcdefgh
8
d8 black king
e7 black rook
d6 white king
d5 white bishop
f1 white rook
8
77
66
55
44
33
22
11
abcdefgh
White to move wins

The winning method is as follows:

1. Rf8+! Re8
2. Rf7!

threatening to switch the rook to the other side and checkmate.

2. ... Re2

This is the best place for the black rook. Alternatives are: (a) 2...Re3 3. Rd7+ Ke8 4. Ra7 Kf8 5. Rf7+ Ke8 6. Rf4 Kd8 7. Be4 a sequence which mirrors the main line from move 8; (b) 2...Re1 and White wins similarly to the main line; (c) 2...Kc8 3. Ra7 Rd8+ 4. Kc6 Kb8 5. Rb7+ Ka8 6. Rb1 Ka7 7. Kc7 and White wins.

3. Rh7 Re1

This idle move maintains the necessity of the black rook on the e file, forcing it to its next best position on e1. White will take advantage of this on move 5.

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+ Kb6 (White wins because the chessboard has only eight files.) 9.Rb8+.

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. If 11...Rc2 or 11...Rc1, then 12.Be6+.

12. Bc4

Stopping the check on d3 and cutting off the rook entirely.

12. ... Kc8
13. Be6+ Kd8
14. Rb8+

and checkmate next move (Müller & Pajeken 2008:178), (Howell 1997:148–50), (Nunn 2007:163–64).

This is an exercise in domination of the black rook.

This method works if the kings are on the central four ranks or files. It does not work if the kings are on the rank or file next to the edge – those positions are a theoretical draw, but difficult to defend. If the kings are on a rank or file on the edge of the board the position is a win, but by a different method (de la Villa 2008:211–13).

Lolli position

Lolli position, 1763

abcdefgh
8
b8 black rook
c4 white bishop
c3 white king
g2 white rook
c1 black king
8
77
66
55
44
33
22
11
abcdefgh
Black to move, White wins

This winning position was discovered by Giambattista Lolli (Benko 2007:154). The position is one rank or file closer to the edge of the board than the Philidor position, so the winning method is slightly different. Switching the attacking rook to the other side of the king is no longer dangerous (Nunn 2002:180–81).

1. ...Rd8 2.Ra2 Rb8 3.Ba6 Rb6 4.Bd3 Rc6+ 5.Bc4 Rb6 6.Rc2+ Kb1 7.Re2 Ka1 8.Re5 Rb7 (or Rb8) 9.Ra5+ Kb1 10.Bd3+ Kc1 11.Ra1+ Rb1 12.Rxb1#

Drawing defenses

Cochrane Defense

John Cochrane

The Cochrane Defense is a drawing method discovered by John Cochrane. The Cochrane Defense is the most popular among grandmasters for this endgame (Nunn 2002:174ff). The basic idea is to pin the bishop to its king when there are at least two ranks or files between it and the defending king.

Accurate play is required for the defense. The defense is most effective near the center of the board, and does not work on the edge (Nunn 2002:174ff). The Cochrane Defense works when:

The Cochrane defense can also be used with a rook against a rook and knight (Howell 1997:150).

Budnikov versus Novik

Budnikov vs. Novik

abcdefgh
8
e8 black king
a7 white rook
e5 white king
e4 white bishop
e2 black rook
8
77
66
55
44
33
22
11
abcdefgh
Cochrane defense. Black to move, draw with either side to move.

The defense is most effective near the center of the board. In this position, if the pieces on the e-file were moved to the f-file, then if 1. Ke5 the response 1... Kg8, puts the black king dangerously close to the corner (Nunn 2007:161ff).

In this position from a 1991 game between Alexandar Budnikov and Maxim Novik, White would like to get his king to d6 and bishop to d5, to win by a method of Philidor (see Philidor position) – however the pin of the bishop to the king prevents it. If White plays 1. Kd5 or 1. Kf5 then Black moves his king in the opposite direction, so if the bishop then moves, the black rook cuts off the white king (Nunn 2002:174ff).

There are some key ideas for the defender to observe:

The game continued:

1... Re1
2. Kd5 Kf8!
3. Bf5 Re7!
4. Ra8+ Kf7
5. Ra1 Kf6
6. Bc8 Re5+
7. Kd6 Re2
8. Rf1+ Kg5
9. Bb7 Re3
10. Kd5 Re2
11. Kd4 Re7
12. Bd5 Re8
13. Rf7 Rb8
14. Ke5 Rb5

and the position is back to the basic Cochrane position, rotated 90 degrees, and the fifty-move rule is closer to coming into effect. The Budnikov versus Novik game continued, with the Cochrane position being reached again. Eventually a draw was claimed by the fifty-move rule (Howell 1997:145–47).

Ljubojević versus Portisch

Ljubojević vs. Portisch

abcdefgh
8
e8 black king
h7 white rook
e5 white king
e4 white bishop
e1 black rook
8
77
66
55
44
33
22
11
abcdefgh
Position after 97... Ke8!

The Cochrane Defense was also used in this 1982 game[4] between Ljubomir Ljubojević and Lajos Portisch. The Cochrane position occurred again on move 114, rotated 90 degrees. The game was drawn on move 127 (Benko 2007:98).

Second-rank defense

The "second-rank defense" is a passive defense with the defending king and rook on a rank or file one over from the edge of the board (e.g. the second or seventh rank or the b or g file). The method is reliable but it is possible to go wrong, especially if the defending king is near the corner (Nunn 2009:201).

Norri versus Atalik

Norri vs. Atalik

abcdefgh
8
b5 black rook
d4 black bishop
e4 black king
c2 white rook
e2 white king
8
77
66
55
44
33
22
11
abcdefgh
White to move

This 1997 game between Joose Norri and Suat Atalık illustrated the second-rank defense.[5] White cannot reach the Cochrane Defense. Attempting to get the rook behind the black king would get to a lost Philidor Position: 87. Rc8? Rb2+ 88. Kf1 Rf2+ 89. Ke1 Kd3. White uses the second-rank defense. White alternates his rook between c2 and d2 until Black tries to penetrate.

87. Rd2 Rh5
88. Rc2 Rh2+
89. Kd1

The defending king can be driven to the edge of the board but then the attacker's rook is under attack, so the king cannot approach.

89... Rh1+
90. Ke2 Rh2+
91. Kd1 Rh3
92. Ke2 Bc3

This is another attempt by Black. It seems that White is in zugzwang and any rook move loses: (93. Rc1 Rh2+ 94. Kd1 Kd3), but White has a good move.

93. Kd1!

Now if 93... Kd3 White has a stalemate defense with 94. Rd2+ so the black king has to back off.

93... Rh1+
94. Ke2

and the game was drawn on move 98 (Nunn 2007:162–63).

Carlsen versus van Wely

Carlsen vs. van Wely

abcdefgh
8
h6 black rook
d4 black bishop
e4 black king
c2 white rook
e2 white king
8
77
66
55
44
33
22
11
abcdefgh
White to move

The second-rank defense was used by 16-year-old Magnus Carlsen in this 2007 game against Loek van Wely.[6]

64. Rd2 Rh3
65. Rc2 Bc3

It is hard to drive the defending king to the edge. After 65... Rh2+ 66. Kd1 the black rook must move and the white king goes back to e2.

66. Kd1

White was in zugzwang and had to temporarily leave the second rank.

66... Kd4

here 66... Kd3 is met by 67. Rd2+

67. Rf2 Kd3
68. Rd2+ Kc4
69. Rf2 Re3
70. Re2 Rd3+
71. Kc2

and the king is back to the second rank. The game continued and the position on move 74 was a reflection of the position on move 66. On move 80 the same defense was set up on the b-file. Black could make no progress and the game was drawn after 109 moves (Nunn 2009:200).

Szén position

Szén position

abcdefgh
8
c7 white rook
b5 black rook
e4 black bishop
e3 black king
d1 white king
8
77
66
55
44
33
22
11
abcdefgh
Black to move, draw

József Szén discovered the Szén position, a defensive drawing position. The kings are opposite in an L-shape and the weaker side's rook defends on the side of his king that has more room (Benko 2007:99). Szén's position is the most important for over-the-board players. Compared to the Philidor Position, the kings are not opposite each other and the defending rook can prevent checkmate. The position is a draw only if there is enough room for the defending king on the side with the rooks (Nunn 2002:183–84).

An example of this defense being used in a game is this 1982 one between József Pintér and Yuri Razuvayev.[7] After 88 moves, the position had a rook and bishop versus a rook. The diagram shows the position after 101. Kd1!, reaching the Szén position. On the 132nd move, White reached a Szén position for the fourth time. The game was drawn on the 138th move (Benko 2007:98–99).

Second Lolli position

Second Lolli position, 1793

abcdefgh
8
b8 black king
c7 black rook
b6 white king
b5 white bishop
d2 white rook
8
77
66
55
44
33
22
11
abcdefgh
White to move, draw

In the second Lolli position, the kings are one row closer to the edge than in the first Lolli position. Unlike the Philidor position and the first Lolli position, this position is a theoretical draw. Several of the moves in the perfect defence are the only move that saves the game (Hawkins 2012:196–97).

See also

Notes

  1. ↑ In 2007 Giddens (page 78) reported 16 out of 16.
  2. ↑ Chess records by Tim Krabbé
  3. ↑ Nikolić vs. Arsović
  4. ↑ Ljubojević vs. Portisch
  5. ↑ Norri vs. Atalik
  6. ↑ Carlsen vs. van Wely
  7. ↑ Pintér vs. Razuvayev (game in database is incomplete)

References

Further reading

This article is issued from Wikipedia - version of the 6/11/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.