En passant: the rule that almost never existed
En passant is arguably the most controversial chess rule and the one beginners most often apply wrongly. It arose from a historical necessity: when the modern rules introduced in the 15th century the possibility for a pawn to advance two squares on its first move (instead of just one), theoreticians immediately saw the problem.
Without en passant, a player could use the two-square advance to “slip past” an enemy pawn with impunity, getting round the defence that pawn exerted. The en passant rule corrects this anomaly by allowing the enemy pawn to capture “as if” the pawn had advanced only one square.
The exact en passant rule
En passant (often abbreviated “e.p.” in notation) applies under very precise conditions:
Condition 1: A pawn must advance two squares from its starting position (rank 2 for White, rank 7 for Black) and finish right next to an enemy pawn (same rank, neighbouring file).
Condition 2: The enemy pawn must be on its 5th rank (rank 5 for White, rank 4 for Black).
Condition 3: The capture must be made immediately, on the very next move. If the player who could have captured en passant plays another move, the right to that capture is lost for good.
Historical fact: En passant took time to be accepted everywhere: in Italy, where “passar battaglia” was played (the pawn could pass without being captured), it was not generally adopted until 1880. It remains one of the rules that most surprises occasional players.
En passant in famous games
Historic games have been decided by en passant at critical moments. In several famous pawn endings, the availability or unavailability of en passant radically changes the evaluation of the position. Game analysts must always check whether en passant is available in the diagram, because its absence can turn a winning position into a draw.
In standard algebraic notation (see our article on chess notation), en passant is written as an ordinary capture: “exd6”, for example, sometimes with the annotation “e.p.” for clarity.
Pawn promotion: the rules and the logic
Pawn promotion is one of the most elegant rules in chess: when a pawn reaches the opponent’s back rank (rank 8 for White, rank 1 for Black), it is transformed into any piece of the player’s choice — except the king. In practice, promotion to a queen is the most common because it is the most powerful piece.
Promotion is compulsory — the pawn cannot remain a pawn once on the last rank. In theory it can become any piece: queen, rook, knight or bishop.
Underpromotion: when a queen would lose
Underpromotion — promoting to something other than a queen — is one of the most counter-intuitive notions in chess for non-specialists. Yet in certain positions, promoting to a knight or a rook is the only way to win, or to avoid a draw.
Promotion to a knight: The most frequent underpromotion. The knight can give check from squares the queen cannot reach immediately, creating a fork or giving time to consolidate the advantage. If a queen on h1 would stalemate the opposing king (a draw by stalemate), promoting to a knight avoids the stalemate while still making a threat.
Promotion to a rook: Rarer, used when a queen would create stalemate but a rook is enough to force mate.
Promotion to a bishop: Extremely rare, almost anecdotal in practical games.
“Pawns are the soul of chess.” — François-André Danican Philidor, Analysis of the Game of Chess (1749)
The pawn race: a fundamental endgame theme
In pawn endings, the question of promotion often becomes the central question. The “rule of the square” is a player’s first tool for judging whether a king can catch a passed pawn. To check whether the king can stop the pawn, you draw a square from the pawn to the promotion rank — if the king enters this square, it can catch the pawn.
Passed pawns and candidate pawns
A passed pawn is a pawn with no enemy pawns on its own file or the adjacent files that could stop it. In an endgame, an advanced passed pawn is often decisive because it forces the opponent to commit material to stopping it, thereby freeing other areas of the board.
Nimzowitsch’s rule on passed pawns is famous: “A passed pawn must be pushed.” This seemingly simple formula conceals a deep strategic truth — a passed pawn that does not advance loses its power to constrain the opponent.
Practise endgames on a quality chessboard
Understanding en passant and promotion calls for practice on a physical board: find a wooden chess set or a connected electronic chess set at Le Palais des Echecs.
Choose your chess set →To complete your mastery of the special rules and technical positions, also discover algebraic notation, which will let you read and record all these positions, and explore the essential tactics so you never miss an opportunity in the endgame.