En passant

Animation of an en passant capture

The conditions for a pawn to capture an enemy pawn en passant are as follows:

• The enemy pawn advanced two squares on the previous move.
• The capturing pawn attacks the square that the enemy pawn passed over.

If these conditions are met, the capturing pawn can move diagonally forward to the square that the enemy pawn passed, capturing the enemy pawn as if it had moved only one square. If the right to capture en passant is not exercised immediately, it is subsequently lost.

Example of an en passant capture

Black to move 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 black pawn is on its initial square. If it moves to f6 (marked by ×), the white pawn can capture it.	White to move 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 moves their pawn forward two squares in a single move from f7 to f5, "passing" f6.	Black to move 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 captures the black pawn en passant, as if it had moved only one square to f6.

Only pawns may capture or be captured en passant; other pieces with the ability to capture diagonally—the king, queen, and bishop—cannot perform the capture.[5] The en passant capture is the only capturing move in chess where the capturing piece moves to a square not occupied by the captured piece.[6]^: 463

In algebraic notation, an en passant capture is notated using the capturing pawn's destination (not the captured pawn's location). In both algebraic and descriptive notation, the move may optionally be denoted by e.p. or similar. For example, in algebraic notation, bxa3 or bxa3 e.p. may be used to represent a black pawn on b4 capturing a white pawn on a4 en passant.[7]^: 216

	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 just played 5...d7-d5. White's e5-pawn can capture en passant.

Some chess openings feature the en passant capture. In the following line from Petrov's Defence, White captures the pawn on d5 en passant on move 6:

1. e4 e5

2. Nf3 Nf6

3. d4 exd4

4. e5 Ne4

5. Qxd4 d5 (see diagram)

6. exd6 e.p.[8]^{: 124–125}

Steinitz vs. Fleissig, 1882

	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

Position after 3.exd6 e.p.

An en passant capture can occur as early as the third move. For example, in the French Defence after 1.e4 e6 2.e5!?,[9]^: 2 if Black responds with 2...d5, White can play 3.exd6 e.p. This occurred in the game Steinitz–Fleissig, Vienna 1882.[10]

An example of overlooking
an en passant capture

	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 to move. Here 1...g5+? loses to an en passant capture checkmate.

In the diagram, the move 1...g5+ may seem to checkmate White, but it is in fact a blunder: White can counter this check with the en passant capture 2.fxg6 e.p.#, which cross-checks and checkmates Black. (Black can draw in the diagrammed position by playing 1...Qxf2+.)

Gundersen vs. Faul, 1928

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 Position after 12...f7-f5	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 After 14...g7-g5, White mates by capturing the pawn en passant.

In a game between Gunnar Gundersen and Albert H. Faul,[11] Black played 12...f7-f5. White could have captured the black f-pawn en passant with his e-pawn, but he instead played:

13. h5+ Kh6 14. Nxe6+

The bishop on c1 effects a discovered check. 14...Kh7 results in 15.Qxg7#.

14... g5 15. hxg6 e.p.#

The en passant capture places Black in double check and checkmate (in fact, White's bishop is not necessary for the mate). An en passant capture is the only way a double check can be delivered without one of the checking pieces moving, as in this case.

The largest known number of en passant captures in one game is three. This record is shared by three games; in none of them were all three captures by the same player. The earliest known example is a 1980 game between Alexandru Sorin Segal and Karl Heinz Podzielny.[12]^: 98–99[13]

In old versions of chess, the pawn could not advance two squares on its first move. The two-square advance was introduced later, between the 13th and 16th centuries, to speed up games. As a result, the en passant capture was also introduced (possibly at a later time) to prevent a pawn evading capture by skipping past a square attacked by an enemy pawn.

The en passant capture was one of the last major additions to European chess.[lower-alpha 2][14]^: 16 In some parts of Europe, particularly in Italy, the rule was not adopted; this alternative rule was known as passar battaglia. In 1880, Italy adopted the rules used by the rest of the world, including the en passant capture, in preparation for the 1881 Milan tournament.[8]^{: 124–125}

In the context of threefold and fivefold repetition, two positions are considered different if the opportunity to perform a given en passant capture exists in one position but not the other.[15]^: 27

When a player is not in check, and capturing en passant is their only legal move, they are forbidden to "claim" a draw by stalemate; they must either perform the move or end the game on their turn via normal means. In his book on chess organization and rules, International Arbiter Kenneth Harkness wrote that people frequently asked if this is the case.[16]^: 49 Chess players debated this point in the 19th century, with some arguing that the right to capture en passant is a "privilege" that one cannot be compelled to exercise. In his 1860 book Chess Praxis, Howard Staunton wrote that the en passant capture is mandatory in such a position; the rules of chess were amended to make this clear.[12][16]^: 49

The en passant capture is often used as a theme in chess problems. According to Kenneth S. Howard, "En passant pawn captures frequently produce striking effects in the opening and closing of lines."[17]^: 106 By retrograde analysis convention, a pawn may be captured en passant only if it can be proven to have advanced two squares on the previous move.

Kenneth S. Howard, 1938

	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 to play and mate in three

In the diagrammed 1938 composition by Howard, the key

1. d4!

introduces the threat of 2.d5+ cxd5 3.Bxd5#. Black can capture the d4-pawn en passant in either of two ways:

1... exd3 e.p.

shifting the e4-pawn from the e- to the d-file, preventing an en passant capture after White plays 2.f4. To stop the threat of 3.f5#, Black can advance 2...f5, but this allows White to play 3.exf6 e.p.# due to the decisive opening of the e-file.

Or Black can play

1... cxd3 e.p.

and now White exploits the newly opened a2–g8 diagonal with 2.Qa2+ d5 3.cxd6 e.p.#.

O. Sommerfeldt, 1902

	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 to play and mate in two

The diagrammed 1902 composition by Sommerfeldt[18] shows the effect of pins on en passant captures.

The key

1. d4!

threatens 2.Qf2#. The moves of the black e-pawn are restricted in an unusual manner. The en passant capture 1...exd3 e.p.+ is illegal (it exposes Black’s king to check), but

1... e3+

is legal. This, however, removes the black king's access to e3, allowing

2. d5#

In most chess variants, pawns move as in standard chess, so the en passant capture is the same. Some larger variants allow pawns to make an initial move of more than two squares, such as the 16×16 game chess on a really big board, in which pawns may move up to six squares forward; such games usually allow an en passant capture on any square the pawn passes.

In some three-dimensional chess variants, such as millennium 3D chess or Alice chess, capturing en passant is allowed, though in the former case, the captured pawn's two-square move cannot have been purely vertical. In 5D Chess with Multiverse Time Travel, capturing en passant is allowed within the spatial dimensions but not between timelines or across time.

Some fairy chess pieces can capture en passant, such as the Berolina pawn.

The en passant capture does not exist in some chess variants, such as Dragonchess and Raumschach. Traditional Asian games of the chess family such as shogi, xiangqi, and janggi have no two-square pawn advance and therefore no en passant capture.

Bibliography

Look up en passant in Wiktionary, the free dictionary.

• Just, Tim; Burg, Daniel B. (2003), U.S. Chess Federation's Official Rules of Chess (5th ed.), McKay, ISBN 0-8129-3559-4
• Winter, Edward (2006), Chess Facts and Fables, McFarland, ISBN 0-7864-2310-2

• En passant (Chess) by Edward Winter