Single Comment

Alex,

En passant is a form of capturing performed by the Pawn upon another Pawn.
 The conditions for this capture are quite specific.  The capturing Pawn
must be located on the fifth rank from the player and in the adjacent file
of the target Pawn.  The target Pawn must have just performed an initial
two-step move which has placed it orthogonally adjacent the capturing
Pawn.  The capturing Pawn then moves to the vacant cell directly behind
the target Pawn and the target Pawn is removed from the field.

The reasoning for this particular form of capture is to allow the Pawn the
option to capture an opposing Pawn which has performed a two-step move,
passing through the cell which would have offered that captured.  The
capturing Pawn is able to obtain that particular position on the field.

Remember that en passant(in passing) can only be performed against an
opposing Pawn which has immediately made a two-step move.  If the player
does not exercise this option on the immediate replying move, they cannot
do so on subsequent turns.

The opportunity to exercise this option may be very infrequent, but can be
quite interesting.