User:JAK/盒/12

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過路兵(法語:En passant,英語:in passing) is a move in the board game of chess. En passant is a special capture made immediately after a player moves a pawn two squares forward from its starting position, and an opposing pawn could have captured it if it had only moved one square forward. In this situation, the opposing pawn may, on the immediately subsequent move, capture the pawn as if taking it "as it passes" through the first square; the resulting position would then be the same as if the pawn had only moved one square forward and the opposing pawn had captured normally. The En passant capture must be done on the very next turn, or the right to do so is lost.[1]

Such a move is the only occasion in chess in which a piece captures but does not move to the square of the captured piece. When claiming a draw by threefold repetition, two positions whose pieces are all on the same squares, with the same player to move, are considered different if there was an opportunity to make an en passant capture in the first position, because that opportunity by definition no longer exists the second time the same configuration of pieces occurs.

In either algebraic or descriptive chess notation, en passant captures are sometimes denoted by "e.p." or similar, but such notation is not required. In algebraic notation, the move is written as if the captured pawn just advanced only one square, e.g, exf6 (or exf6 e.p.) in the illustration below.

Illustration

Example of en passant
Black to move
abcdefgh
8
f7 black pawn
f6 black cross
e5 white pawn
8
77
66
55
44
33
22
11
abcdefgh
The black pawn is in its initial location. If it moves to f6 (×), the white pawn could capture it.
White to move
abcdefgh
8
f6 black cross
e5 white pawn
f5 black pawn
8
77
66
55
44
33
22
11
abcdefgh
Black moved his pawn forward two squares from f7 to f5, "passing" f6.

Black to move
abcdefgh
8
f6 white pawn
8
77
66
55
44
33
22
11
abcdefgh
On the next move, White captures en passant, capturing the pawn as if it had moved to f6.

Example in opening

abcdefgh
8
a8 black rook
b8 black knight
c8 black bishop
d8 black queen
e8 black king
f8 black bishop
h8 black rook
a7 black pawn
b7 black pawn
c7 black pawn
d7 black circle
f7 black pawn
g7 black pawn
h7 black pawn
d6 black cross
d5 black pawn
e5 white pawn
d4 white queen
e4 black knight
f3 white knight
a2 white pawn
b2 white pawn
c2 white pawn
f2 white pawn
g2 white pawn
h2 white pawn
a1 white rook
b1 white knight
c1 white bishop
e1 white king
f1 white bishop
h1 white rook
8
77
66
55
44
33
22
11
abcdefgh
Petrov line, after 5... d7-d5, the white pawn on e5 may capture en passant.

In this line from the Petrov Defence, White can capture the pawn on d5 en passant on his sixth move.

  • 1. e4 e5
  • 2. Nf3 Nf6
  • 3. d4 exd4
  • 4. e5 Ne4
  • 5. Qxd4 d5 (diagram)
  • 6. exd6Hooper & Whyld 1992,pp.124-25).

Example from game

Gundersen-Faul, 1928
abcdefgh
8
a8 black rook
c8 black bishop
d8 black queen
f8 black rook
a7 black pawn
b7 black pawn
g7 black pawn
e6 black pawn
g6 black king
d5 black pawn
e5 white pawn
f5 black pawn
g5 white knight
b4 black bishop
d4 black knight
g4 white queen
h4 white pawn
c3 white knight
a2 white pawn
b2 white pawn
f2 white pawn
g2 white pawn
a1 white rook
c1 white bishop
e1 white king
h1 white rook
8
77
66
55
44
33
22
11
abcdefgh
Position after 12... f7-f5.
Gundersen-Faul
abcdefgh
8
a8 black rook
c8 black bishop
d8 black queen
f8 black rook
a7 black pawn
b7 black pawn
e6 white knight
h6 black king
d5 black pawn
e5 white pawn
f5 black pawn
g5 black pawn
h5 white pawn
b4 black bishop
d4 black knight
g4 white queen
c3 white knight
a2 white pawn
b2 white pawn
f2 white pawn
g2 white pawn
a1 white rook
c1 white bishop
e1 white king
h1 white rook
8
77
66
55
44
33
22
11
abcdefgh
After 14... g7-g5. White wins by taking the pawn en passant, which results in checkmate.

In this game [2] between Gunnar Gundersen and A. H. Faul, Black has just moved his pawn from f7 to f5. The white pawn on e5 could capture the f-pawn en passant, but White had a different idea:

  • 13. h5+ Kh6
  • 14. Nxe6+ g5
  • 15. hxg6 e.p. #

Capturing the g-pawn en passant resulted in checkmate.

Historical context

Historically, allowing en passant is one of the last major rule changes in European chess that occurred in the 14th to 15th century, together with the introduction of the two-square first move for pawns, castling, and the unlimited range for queens and bishops. Because of their separation from European chess prior to that period, the Asian chess variants do not feature any of these moves.

The motivation for en passant was to prevent the newly-added two-square first move for pawns from allowing them to evade capture by an enemy pawn. Specifically, it should still allow pawns on the player's fifth rank the opportunity to capture a pawn on an adjacent file which advances two squares from its starting square.

See also

Notes

References