Chess is an accurate wargame, Jim Dunnigan argues, for the period it covers, the pre-gunpowder period:
Chess is a highly stylized game. It is always set up the same way, the playing pieces and the playing board are always the same. The board is quite simple. Each of the pieces has clearly defined capabilities and starting positions, much like soldiers in ancient warfare. Given that ancient armies were so unwieldy and communication so poor, it is easy to see why each player in chess is allowed to move only one piece per turn. Because the armies were so hard to control, the battles were generally fought on relatively flat, featureless ground. Then, as now, the organization of the army represented the contemporary social classes. Thus the simularity between chess pieces and the composition of ancient armies.
As a minor point on the history of chess, the “queen” was, until quite recently, called not the “queen” but the “general,” “prime minister,” or other similar titles to represent the piece’s true function, namely, the actual head of the army who had under his personal command the most powerful troops. This is why the “queen” piece is so powerful. Not only does it represent the single best body of troops, but also the very leadership of the army. The king, on the other hand, is indeed the king of the kingdom, without whose presence the army is lost. Thus, the king is not necessarily a soldier of any particular talent. During the battle his main function is to survive and to serve as a symbol, a rallying point for his army.