Peasant unit

The pawn unit is a system for quantifying the value of chess pieces . As a basic benchmark, the value of a pawn is set equal to 1 and the values ​​of the other chess pieces are given relative to it. The pawn unit is used by chess players and chess computers to assess the position and to estimate the consequences of a move.

Classically, the figures are rated as follows:

figure	Farmer	Jumper	runner	tower	lady	king
value	1	3	3	5	9	∞

The king has no value in pawn units because he cannot be captured. In endgame situations where no immediate danger of Matt and the king will be active, combat value is usually between a minor piece (bishop or knight) and a tower.

From the figures given it follows that if the material conditions are unequal, for example, two towers are usually stronger than a lady or two minor pieces are usually stronger than one tower. Runner and jumper are rated as roughly equal. The runner can work at greater distances and on average controls more squares than the knight, but he is bound to his field color. Since both bishops together avoid this disadvantage, the bishop pair is usually stronger than two knights in the middle and endgame.

Since two bishops can be stronger than two knights, it turns out that the pawn unit is only to be understood as a rule of thumb that becomes imprecise in certain positions. So it can make perfect sense to sacrifice a higher value piece for a piece with a lower pawn value, if this gives you a positional advantage.

quality

The term quality is common for the added value of a tower compared to a lightweight figure . The exchange of one's own minor figure for an opponent's tower is called a gain in quality , for the opponent it is a loss of quality . A quality sacrifice is the deliberate exchange of a tower for a minor figure. Associated with this is the need to obtain other advantages in return. This can be, for example, a gain in speed or a positional advantage.

Colloquially, chess players often use the corruption jellyfish for quality. The traditional club newspaper of the Schach-Club Kreuzberg e. V. in Berlin calls itself the cross jellyfish , for example .

Changes in the course of the game

Since the position plays a role in the evaluation of the pieces, it follows that the values ​​also change slightly in the course of the game. Cecil Purdy estimated 3.5 pawn units for the minor pieces in the opening and middle game , but only 3.0 in the endgame . Further examples are:

• In the middlegame a queen is worth roughly the same as two rooks, but a little less in the endgame. Without any other pieces in the game, two towers are worth roughly the same as a queen and a pawn.
• In the opening and in the middle game, a rook and two pawns are weaker than two bishops and about as strong as two knights. In the final game, however, a tower and two farmers are as strong as two runners, and a tower and a farmer is about two jumpers.
• Runners are often stronger in opening than rooks. This relationship turns around as the game progresses.
• The pawns also change their value: In the opening and in the middle game, the central pawns are more valuable than the outer ones, but in the endgame the outer pawns are significantly more valuable, as they are easier to convert . With around 14 pieces on the board, all pawns are worth roughly the same.

Computer chess

The pawn unit is also used in computer chess . Modern chess programs, however, calculate with more precise values ​​that are multiplied by a hundred for faster calculation. In addition, they take into account the position and thus change the individual values ​​depending on the position, so they deduct something from the pawn value of a piece if this is unfavorable. In this way the programs can decide on the best possible move and also determine how the value of the position of the two players would change after a move. Calibrating these values ​​as precisely as possible, usually based on the results of position tests, is one of the most important tasks of a chess program.

For chess programs in particular, there have been several attempts in the chess literature to specify the classical values. As early as the Handbuch des Schachspiels of 1852 it was emphasized that the current value of a certain piece depends heavily on its position and movement possibilities. Even Emanuel Lasker wrote in his chess textbook that comparative values between the figures only ceteris paribus apply.

For example, the following adjustments to the classic values ​​were proposed, with Larry Kaufman adding a bonus of 0.5 pawn units for a pair of bishops:

figure	Farmer	Jumper	runner	tower	lady	source
value	1.00	3.05	3.50	5.48	9.94	Howard Staunton
value	1.00	3.25	3.25	5.00	9.75	Larry Kaufman
value	1.00	3.20	3.33	5.10	8.80	Hans Berliner

Individual evidence

1. ↑ website of the club magazine Cross jellyfish , accessed on February 21 2011th
2. ↑ Cecil Purdy : CJS Purdy on the Endgame . Thinker's Press, 2003, ISBN 978-1-888710-03-8 .
3. ^ Lew Alburt , Nikolai Krogius : Just the Facts !: Winning Endgame Knowledge in One Volume . 2005, ISBN 1-889323-15-2 .
4. ↑ Yasser Seirawan : Winning Chess Endings . Everyman Chess, 2003, ISBN 1-85744-348-9 .
5. ^ ^{A b} Hans Berliner : The System: A World Champion's Approach to Chess . Gambit Publications, 1999, ISBN 1-901983-10-2 .
6. ^ Evaluation of material imbalances
7. ^ Howard Staunton : The Chess Player's Handbook . Hardinge Simpole Ltd, 2003, ISBN 978-1-84382-088-8 .