Book of Chess, Its Problems, and Its Subtleties

...representing the Vizier original: "al-Wazir," the Counselor or Queen.; the Rook in place of the Commander of the Army; the Horse in place of the Cavalrymen; the Elephant in place of the Fortresses; and the Pawns in place of the Infantry. This is the division of the pieces of Chess.

As for his wisdom in the arrangement

He placed the Shah original: "al-Shah," the King. in the center because the King must not be [exposed] in the heart of the army This likely refers to the front lines or the thick of the fray.. He placed the Vizier next to him because the Vizier must be in close proximity to the King. He placed the Elephant after the Vizier because it is necessary for the most fortified positions in the battle to be where the King and his Vizier are stationed. He placed the Horse original: "al-Faras," the Knight. between the Elephant and the Rook because the cavalry must be positioned alongside the defenders of the fortresses. He placed the Rook original: "al-Rukh." next to the Horse because the Commander of the Army is the officer who organizes the right and left wings. He placed the Pawns in front of all of these in a row because the infantry are those who advance first in war. This is his wisdom regarding the arrangement of the pieces.

As for his wisdom regarding the movement of the pieces during play

This mirrors the nature of disputes and skirmishes. He made the movement of the Pawn original: "al-Baydaq." a single square in a straight line because it is not for the foot soldier to stray from his assigned position in the battle, nor should he advance except by The board: movement and capture crawling forward original: "zahfan," a slow, steady military advance.. He made the Pawn's method of capture diagonal because a soldier only gains an advantage over his opponent by way of stealth during a close-combat duel original: "al-munaqafah," a term for striking at an opponent's head or upper body during a skirmish.. Furthermore, he mandated that the Pawn shall become a Farzan original: "Farzan," the Counselor or Queen. if it manages to reach the far end of the board.