Impulse-based turn

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An impulse-based turn system is a game mechanic where a game turn is broken up into a series of discrete, repeating segments, or impulses. It can be considered a fairly complex mechanic, but has been used in three games that have enjoyed long-term success, the wargames Star Fleet Battles and Car Wars, and the Hero System role-playing game (also known as Champions or Fantasy Hero).

It is most often seen in games that feature high-paced combat where units can move much further in one turn than common effective weapons ranges. (In Star Fleet Battles, a ship may move as far as 31 hexes in a single turn, and can usually move 20. 'Effective' weapon's range is generally 4-8 hexes at best.)

An obvious alternative would be to make the impulses into full-fledged turns. However, this will generally cause a lot of extra bookkeeping, as things that are abstracted for the full turn (like acceleration), get repeated in every former impulse (now turn). Instead, impulses allow for movement to be spread out across the impulses with each player acting simultaneously and reacting to the situation (with maneuver or weapons fire), with minimal interference from the other systems in the game.