The Empire! system is the card-based system that powers the two Napoleonic RPGS from Omnihedron Games, namely Duty & Honour and Beat to Quarters.
The Empire! system was first published in Duty & Honour, and saw additional rules published in the 1809 Miscellany.
A slightly revised and expanded version of the Empire! system was then published in Beat to Quarters. This second RPG contained expansions to the core system to deal with things like ship to ship combat and boarding.
The recently released 1810 Miscellany contains rules for bringing the slightly different versions of the Empire! system extant in D&H and BtQ into harmony.
In play the Empire! system is pretty simple to grasp and quick to execute. Utilising a standard deck of playing cards, conflicts are resolved by "flopping" a number of cards and trying to match either the suit or the number on a target card flopped from the GM's own deck of cards.