From the rear cover:

This game is a simulation of real-world events. It is played on a map that is a simplified terrain reproduction of the actual battlefield. A grid of hexagons printed over the map is used to regulate movement and position such as the squares on a chess board. The pieces in the game represent the actual military units that took part in the historical conflict. The large numbers on the pieces indicate the relative strength of these units. Each Player maneuvers his pieces on the map to engage those of the enemy. Battles take place when units are adjacent to enemy units. The total relative strengths of the involved units are compared. The attacking Player consults a simple probability table (the Combat Results Table) to determine the outcome of each battle. First one Player moves his units and conducts attacks, and then the other. The game proceeds this way (for a specified number of turns) as the Players try to achieve the historical objectives set forth in the rules. The final outcome of the game can be very different from the actual historical result. This gives Players a chance to "change history." No prior knowledge of history or military tactics is required to play the game - just a little ingenuity and common sense.