From the games intro:-

WAR IN NAPOLEON’S TIME
Dickens & Greenwood Games are not historical simulation games, such as you may have seen. They are historically based, in that they recreate the military capacities of a given era in the history of warfare, but they are abstract. They do not restrict the player to the circumstances of a given campaign, or to the capacities of actual units, or to the style of an actual leader. Both players are equipped with units whose capacities are equivalent to those of the era in which the game is set. But their forces and situations are abstract and equal, and each player must win or lose according to his own skill and judgment, without the influence of luck or of pre-existing historical conditions. There are no dice or chance outcomes.

Chris's Comments
The game is played on a map divided into equal squares using units to represent Infantry, artillery and Cavalry. To make the game balanced the map is also symmetric about the line dividing the two sides. The game is won by either eliminating all field units, or by blocking the roads leading from the opponents city or occupying the opponent city.