Chess|Pawn

Unlike other pieces in Chess, a pawn moves differently when capturing an opposing piece than it does when moving without capture.

• When capturing an opposing piece, and only then, a pawn moves one cell diagonally forward, either to the left or right.
• When not capturing, a pawn advances one cell directly forward if it is not obstructed by another piece of the same or opposing color.
• The first time a particular pawn is moved from its initial position, and only then, it may optionally advance two cells forward as long as both the cell to which it moves and the cell over which it moves are both unoccupied.
• A pawn is not entitled to "escape" capture by an opposing pawn (and only a pawn, not other pieces) by virtue of this special first move. If, in making its initial two-square first move, a pawn lands adjacent to an opposing pawn that would have been entitled to capture the moving pawn on its turn had the moving pawn only advanced one square, that opposing pawn now has the option of capturing the moving pawn en passant (or "in passing") as if it had advanced only one square. To do this, the capturing pawn moves into the empty square over which the moving pawn passed, and the moving pawn is removed from the board. This option is available to the opposing pawn only at its first opportunity. If the opposing player chooses not to capture the moving pawn immediately and makes another move, that player's right to make the en passant capture is lost and may not be made on any subsequent move.
• A pawn that advances all the way to its eighth rank (the opposing player's first rank) is promoted to a queen, rook, bishop, or knight as the player chooses (the other pieces already on the board make no difference; a player is entitled to have several queens, for example, if he promotes several pawns). This promotion occurs immediately upon the pawn's advancement, before the opposing player's next move (if the new piece, for example, checkmates the opposing player, the game is won).

Pawns are the weakest and most numerous of the chess pieces, but still play an important part in the game. They represent infantry, or more particularly pikemen.