original: Normally a pawn moves by advancing a single square, but the first time each pawn is moved from its initial position, it has the option to advance two squares.
simplifications: Normally a pawn moves by advancing a single square.  The first time each pawn is moved from its initial position, it has the choice to go forward two squares. Normally a pawn moves by a single square, but the first time pawn is moved it can move two squares. Pawns normally can only move by one square but the first move can be by two squares. Normally a pawn moves by advancing a single square. The first time each pawn is moved from its initial position, it has the option to advance two squares. Normally, a pawn moves forward a single square. However, the first time each pawn is moved from its starting position, it can move forward two squares. Normally a pawn moves by moving forward a single square. However the first time each pawn is moved from its start, it can move two squares. A pawn can move two squares on its first move. Otherwise a pawn can only move forward one square. Normally a pawn moves one square at a time. The first time a pawn moves, it can move two squares. A pawn moves forward a single square normally. But the first time a pawn is moved it can advance two squares. On the first movement only, a pawn has the option to move two squares rather than the normal one square.