En passant and promotion: the pawn’s two special moves

1. En passant

When a pawn moves two squares on its first move and lands right next to an enemy pawn, that enemy pawn may capture it as if it had moved only one square: it moves diagonally to the square the pawn "skipped", and the captured pawn leaves the board.

You can only do it on the very next move. If you don’t take it then, the chance is gone. And, like any move, you can’t make it if it leaves your king in check.

2. An example

Your white pawn is on e5. Black plays d7-d5: their pawn passes yours. On your next move you can capture en passant with exd6: your pawn goes to d6 and Black’s d5 pawn disappears. It is written like any pawn capture.

3. Promotion

When a pawn reaches the last rank (rank 8 for White, rank 1 for Black) it immediately becomes a queen, rook, bishop or knight, its owner’s choice. It doesn’t matter how many queens are already on the board.

A queen is the usual choice, being the strongest piece. But sometimes a knight gives checkmate or avoids stalemate, and promoting to a rook or bishop can avoid leaving the opponent without a move (stalemate) when you were winning.

4. How it works on Vexply

En passant shows up among the pawn’s highlighted squares only when it’s allowed. When you promote, the game shows the four pieces to choose from; against the AI, the computer picks its own piece too.