En passant

[6]: 463 Because many casual players are unfamiliar with or misunderstand the en passant rule, administrators on internet chess sites frequently receive erroneous complaints of bugs, cheating or hacking.

White could have captured the black f-pawn en passant with his e-pawn, but he instead played: The bishop on c1 effects a discovered check.

The en passant capture places Black in double check and checkmate (in fact, White's bishop is not necessary for the mate).

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.

In his book on chess organization and rules, International Arbiter Kenneth Harkness wrote that people frequently asked if this is the case.

[18]: 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.

According to Kenneth S. Howard, "En passant pawn captures frequently produce striking effects in the opening and closing of lines, both for white and black.

"[19]: 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.

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.

The diagrammed composition by Sommerfeldt[20] shows the effect of pins on en passant captures.

The en passant capture 1...exd3 e.p.+ is illegal (it exposes Black’s king to check), but is legal.