How I Write Skirmish War Games: Chance and Punishment
Dice and probability are an inevitability in any war game, however a distressing number of games include it simply because "war games include probability". There are three good reasons to include probability:
1) To provide constant interesting tactical choices. Without random events skirmish games would be little more than sloppy games of chess, predictable but without the strictures that make such predictability interesting. Chance allows a skirmish game to have a player formulate a plan, see it go wrong and build a new plan on the fly, which is fun. It is vital though that such probability allows enough predictability to formulate plans.
2) To keep hope alive. Outnumbered or outclassed troops should still have a lucky shot at defeating their opponents. Each player should have good reason to keep playing until the play is done and not before. The added advantage is that forces can begin games with lots of small chances of victory or a few large chances. It is vital however that chasing hope for a losing player does not result in destroying any point of playing well for the winning player. If every player constantly has a reasonable chance of victory whatever they do there is very little point paying any attention to the game itself.