There are a number of different Chess moves which exist that have all been popularized with special names to clarify exactly what they stand for. Sometimes these moves are named after the person who frequented them, being called a special form of offense or defense. Occasionally, these moves are named after an abstract theory about the game itself. An En Passant, however, is named for exactly what it stands for. Taken from the French for, "in passing," the term describes exactly what is happening on the board with the move.

Chess used to play by somewhat different rules, with castling never formerly being allowed, Queens and Bishops were limited in how far they could move in any one direction, and Pawns were never allowed to move more than one space at a time. In the 14th and 15th Centuries, however, the rules of Chess began to slowly change and all of the above mentioned examples now became permissible. This did pose a problem, though, with some of the Pawns. When Pawns were allowed to move up to two spaces on their first move, they could sometimes land in a position which would place them directly next to a Pawn of an opposite color. Being directly next to that Pawn of the opposite color, the original Pawn became unable to be captured. This would often result in an excess of Pawns on the board and became problematic to many of the strategies of the game.

To avoid the complications that this issue started to arise, another rule was added to the specifics of Chess. Rather than remove the rule which allowed Pawns to be removed two spaces, a special rule was customized to make up for the problem that Pawns which landed next to each other could pose. If a Pawn takes its initial move of two spaces and lands directly next to another Pawn of the opposite color, thus preventing the Pawn from being captured by normal rules, En Passant can come into play. The player of the opposite Pawn is allowed to move their Pawn one space diagonally, so that it is now directly behind the original Pawn. The original Pawn is then captured, as if it had never been allowed to move the original two spaces and only could move one instead. This places the Pawn of the opposite color into the space that the original Pawn would have occupied and the original Pawn is considered a captured piece.

En Passant is helpful in the fact that it helps to clear the chessboard a bit before heavy strategic decisions begin to come into play. Having too many pawns on the board can clutter a space and begin to hinder some of the more brilliant Chess strategies that players could enact. Space is sometimes needed on a board to play out a battle and the removal of pawns can be a very important part of a player's strategy. The beauty of the En Passant move is that it allows a player on the offense to not be thwarted by special Pawn movements, allowing them to strike while they have an opportunity.