Pawn (chess)

Unlike other pieces, the pawn does not capture in the same direction that it moves. A pawn captures diagonally forward one square to the left or right (see diagram).

Another unusual rule is the en passant capture. It can occur after a pawn advances two squares using its initial two-step move option, and the square passed over is attacked by an enemy pawn. The enemy pawn is entitled to capture the moved pawn "in passing" – as if it had advanced only one square. The capturing pawn moves to the square over which the moved pawn passed (see diagram), and the moved pawn is removed from the board. The option to capture the moved pawn en passant must be exercised on the move immediately following the double-step pawn advance, or it is lost for the remainder of the game.[2]

Example of regular capturing

	a	b	c	d	e	f	g	h
8									8
7									7
6									6
5									5
4									4
3									3
2									2
1									1
	a	b	c	d	e	f	g	h

The pawn may capture either the rook or the knight, but not the bishop, which blocks the pawn from moving directly forward.

Example of en passant

	a	b	c	d	e	f	g	h
8									8
7									7
6									6
5									5
4									4
3									3
2									2
1									1
	a	b	c	d	e	f	g	h

Assuming the black pawn has just moved from c7 to c5, the white pawn can capture it by moving to c6.

En passant was added in the 15th century to compensate for the then newly added two-square initial move rule (Hooper & Whyld 1992:124). Without en passant, a pawn on its initial square could safely bypass a square controlled by an advanced enemy pawn.

A pawn that advances all the way to the opposite side of the board (the opposing player's first rank) is promoted to another piece of that player's choice: a queen, rook, bishop, or knight of the same color. The pawn is immediately (before the opponent's next move) replaced by the new piece. Since it is uncommon for a piece other than a queen to be chosen, promotion is often called "queening". When some other piece is chosen it is known as underpromotion. The piece most often selected for underpromotion is a knight, used to execute a checkmate or a fork to gain a significant net increase in material. Underpromotion is also used in situations where promoting to a queen would give immediate stalemate. The choice of promotion is not limited to pieces that have been captured; thus a player could in theory have as many as ten knights, ten bishops, ten rooks or nine queens on the board simultaneously. While this extreme would almost never occur in practice, in game 11 of their 1927 world championship match, José Raúl Capablanca and Alexander Alekhine each had two queens in play from move 65 through move 66.[3] While some finer sets do include an extra queen of each color, most standard chess sets do not come with additional pieces, so the physical piece used to replace a promoted pawn on the board is usually one that was previously captured. In informal games, when the correct piece is not available, a second queen is often indicated by inverting a previously captured rook, or placing two pawns on the same square. In tournament games however this is not acceptable, and may result in the arbiter ruling that the upturned piece is, in fact, a rook.[4]

	a	b	c	d	e	f	g	h
8									8
7									7
6									6
5									5
4									4
3									3
2									2
1									1
	a	b	c	d	e	f	g	h

Black has an isolated pawn on d5.

Pawns on adjacent files can support each other in attack and defense. A pawn which has no friendly pawns in adjacent files is an isolated pawn. The square in front of an isolated pawn may become an enduring weakness. Any piece placed directly in front not only blocks the advance of that pawn, but cannot be driven away by other pawns.

In the diagram, Black has an isolated pawn on d5. If all the pieces except the kings and pawns were removed, the weakness of that pawn might prove fatal to Black in the endgame. In the middlegame, however, Black has slightly more freedom of movement than White, and may be able to trade off the isolated pawn before an endgame ensues.

From Fine & Benko

	a	b	c	d	e	f	g	h
8									8
7									7
6									6
5									5
4									4
3									3
2									2
1									1
	a	b	c	d	e	f	g	h

White wins with either side to move

A pawn which cannot be blocked or captured by enemy pawns in its advance to promotion is a passed pawn. In the diagram, White has a protected passed pawn on c5 and Black has an outside passed pawn on h5. Because endgames are often won by the player who can promote a pawn first, having a passed pawn in an endgame can be decisive – especially a protected passed pawn (a passed pawn that is protected by a pawn). In this vein, a pawn majority, a greater number of pawns belonging to one player on one side of the chessboard, is strategically important because it can often be converted into a passed pawn.

The diagrammed position might appear roughly equal, because each side has a king and three pawns, and the positions of the kings are about equal. In truth, White wins this endgame on the strength of the protected passed pawn, regardless which player moves first. The black king cannot be on both sides of the board at once – to defend the isolated h-pawn and to stop White's c-pawn from advancing to promotion. Thus White can capture the h-pawn and then win the game (Fine & Benko 2003:56).

	a	b	c	d	e	f	g	h
8									8
7									7
6									6
5									5
4									4
3									3
2									2
1									1
	a	b	c	d	e	f	g	h

Black has doubled c-pawns.

After a capture with a pawn, a player may end up with two pawns on the same file, called doubled pawns. Doubled pawns are substantially weaker than pawns which are side by side, because they cannot defend each other, they usually cannot both be defended by adjacent pawns, and the front pawn blocks the advance of the back one. In the diagram, Black is playing at a strategic disadvantage due to the doubled c-pawns.

There are situations where doubled pawns confer some advantage, typically when the guarding of consecutive squares in a file by the pawns prevents an invasion by the opponent's pieces.

Pawns which are both doubled and isolated are typically a tangible weakness. A single piece or pawn in front of doubled isolated pawns blocks both of them, and cannot be easily dislodged. It is rare for a player to have three pawns in a file, i.e. tripled pawns.

In chess endgames with a bishop, a rook pawn may be the wrong rook pawn, depending on the square-color of the bishop. This causes some positions to be draws that would otherwise be wins.

Illustration by Peter Newell. "The chessmen were walking about, two and two!" (Through the Looking-Glass, and What Alice Found There by Lewis Carroll, 1871). Most of the main characters are represented as chess pieces in the chess-themed story, with Alice, the main protagonist, represented as a pawn.

Although the name origin of most other chess pieces is obvious, the etymology of pawn is fairly obscure. It is derived from the Old French word paon, which comes from the Medieval Latin term for "foot soldier" and is cognate with peon. In most other languages, the word for pawn is similarly derived from paon, its Latin ancestor or some other word for foot soldier. In some languages the pawn is named after a term for "peasant" or "farmer", reflecting how the lower orders were conscripted as footsoldiers in wartime: Hungarian paraszt, Slovene kmet, German Bauer, Danish/Norwegian/Swedish bonde, Latvian bandinieks.[9] In Irish, the term fichillín, a diminutive of ficheall ("chess") is sometimes used, though the term "ceithearnach" ("foot soldier") is also used. In Thai the pawn is called เบี้ย (bîia), which signifies a cowrie shell or a coin of little value. In Turkish the pawn is called piyon, borrowed from the French word Pion in the 19th century.

Pawn is often taken to mean "one who is easily manipulated" or "one who is sacrificed for a larger purpose". Because the pawn is the weakest piece, it is often used metaphorically to indicate unimportance or outright disposability; for example, "She's only a pawn in their game."