Astromachia is a starship combat simulation boardgame for two or more players. Normally, each player controls one ship, but experienced players should be able to fly three or four ships without too much difficulty. Astromachia is distinguished from other games in this genre by three features: fast, highly interactive play; realistic Newtonian movement; and a strong sense of three-dimensionality. Players alternate taking very simple actions, such as maneuvering, angling shields, or firing a weapon. This prevents long waits for a chance to do something. Movement follows Newton's laws of motion. A ship doesn't always move in the direction it is facing. Furthermore, if a ship gets going too fast in one direction, it has to turn around and fire its engines to slow down. Astromachia is fully three-dimensional. Ships can fly at different altitudes, and can move up or down as easily as moving north, south, east, or west. (These directions are with reference to the local star system, not to a planet.) A ship can have any of 24 different orientations, and is damaged differently depending on whether the damage is coming from the fore, aft, port, starboard, dorsal, or ventral side.