I'm considering a mechanic where players have a hand of five victory and five defeat cards. When they are attacked by another player, they get to decide whether they win or lose the battle by playing one of the cards. Simple as that.
So in the end it would come down to players strategizing when and where to lose their battles, as winning or losing in different conditions would have different effects. You could try to goad a player into using up his victory cards by repeatedly attacking him with a weak unit or you could choose to lose a number of battles so that you could win a number of them at a more advantageous time and place.
1.) Does this sound interesting/appealing?
2.) Do you know of any other games using this?
A key question on whether this mechanic would work is how many battles there are and what is the rule for refreshing your hand.
If there are <10 battles, then there is little incentive for playing the losing cards.
If there are =10 battles, then the game would certainly have a bluffing mechanic but may need something more for longevity once the bluffing mechanic wears thin. (Then again, it might not. Who would have thought that RPS would be a tournament sport. http://en.wikipedia.org/wiki/Rock-paper-scissors#World_Rock_Paper_Scisso...)
If there are >10 battles, then you need a rule for refreshing your hand. The way you make this rule would drive the strategy of the game.
You mention a "weak unit", which indicates that units could have numerical values. In this case, it sounds like your mechanic is "play one card to modify combat strength, highest wins".
The game could definitely have merit as a multiplayer game, though it may allow people to abuse the system through alliances (depending on how the card refresh rule was stated). E.g. two allies make insignificant attacks against each other to get rid of their low cards, which lets them play their high cards against their real enemies.
Good points. The weak or strong units can't have anything to do with military power then, maybe just VP values.
I'm thinking about just letting the players take the 10 cards back into their hand when they're done.
Don't know if you want a random refresh mechanic but how about you roll a d6 at the end of each round and if it comes up less than the number of Defeat cards played then you pick up all played cards (or you play all your cards)
I would direct you to the Fantasy Flight version of the classis Condottieri. In this game, players have a hand of cards which are either strong, weak, or have special powers, and there is a lot of bluffing and drawing out of opponents' forces.
This might be instructive for your mechanical conundrum.
I think the key element would be the incentives for which battles to win or lose. I think it would be important for players to have a clear idea of what they stand to give up (or get) now and what that will help them get (or force them to give up) later. Just because they have a clear idea doesn't mean it will work out that way, but it'll add more excitement and intensity the better they understand the stakes and the rewards.
Forcing players to chose between long term and short term gains (or losses) is pretty common, but I'm not personally aware of any games that do so in the manner your describing. I think what's most unique about your idea is how directly it forces players to make that decision, and how directly players can confront one another and throw off each other's strategies (You may want to save up cards and unleash a devastating barrage late in the game, but if your opponents keep going after you, you'll be losing life at such a rate that you'll have to compromise your initial strategy and come up with a new plan). It's an interesting dynamic, and has a lot of potential once it gets fleshed out.