Clauswitz' War: Theatre-Level Napoleonic Campaign Rules is a set of free wargames rules for Napoleonic campaigns. The author writes:
These rules are designed to be used to represent theatre-level campaigning with armies of several corps per side during the Napoleonic period. Each turn is a day, and maps covering an area from 100 - 500 miles on a side with good detail (roads, rivers, towns) should be used. The intent of these rules is not to depict campaigning 100% accurately, but to provide a referee with basic guidelines for running a Kriegspiel-type game for the generation of tabletop engagements. All dice are ordinary 6-sided dice.