PnPRPG Combat system

The heart of a PnP RPG: conflict management (preferably with swords and/or sorcery).

Our goal?  Tradeoffs.  Sid Meiers' interesting choices.

Initiative:
Whomever has the highest initiative (however that is calculated) goes first.  Each character then chooses from amongst the players who have yet to go, which shall come next.  (That is, if it is your turn, you get to pick whose turn comes next, provided it is someone who hasn't gone yet).  This continues until all characters have taken their turn.  The last character to act chooses who will act first in the next round.

Battle Threshold:
Everyone has a threshold representing the amount of attention and reflex they can devote to doing stuff each round.  This will often be a number in the neighborhood of 7 (as a starting assumption, pending other mechanics).

Acting in combat causes one to accumulate stress that is compared to this threshold, perhaps in the form of counters.  Reflexes, like parries, result in one point of stress accumulating.  Acts that require conscious decision or commitment, like dodges, grabbing items off the table, and so forth, accumulate two points of stress.  Taking action to harm another character, due to the amount of mental commitment needed to do so, accumulates three points of stress.

There is no limit to the amount of stress a character can accumulate in this fashion.  However, the amount of stress over and beyond the threshold is applied as a penalty to any actions that require a roll or comparison.  That is, if you decided to attack an enemy, you have a threshold of 6, and you have 8 action stress, your attack has a -2 penalty applied to all rolls.  Moreover, as your attack accumulates an additional 3 stress, any further actions you take will suffer a -5 penalty to all rolls(!).

Stress accumulates after the act that causes it (so, the attack in the example does not start out with a -5 penalty, but only the -2).

When a character receives his turn, it is up to the player of that character how much stress to accumulate 'doing stuff', including attacking, and how much to hold back, to enable defenses to subsequent attacks.  This means the advantage of going first is setting the pace; the advantage of going last is knowing you can safely use up the rest of your threshold.

At the start of a new round, the total Battle Threshold of each character is subtracted from that character's action stress; if they had an amount equal to or less than their threshold, they now have zero stress.  If their stress exceeded their threshold, however, there will be residual stress.  This simulates actions that leave one more open, or need recovering from, and so forth.

Any player may respond to an action directed at him with any reflex, action, or attack (e.g. you can attempt to parry or dodge an incoming attack, or simply choose to attack simultaneously).  These responses are considered simultaneous to the action to which they respond.

Any player may choose to act out of turn at any time, at the cost of accumulating double stress for whatever action they take.  (You can, in fact, dive in front of an attack meant for an ally -- but you will accumulate four stress instead of two because it's not your turn).

Should two characters both attempt to act out of turn, their actions are simultaneous unless one of them chooses to accumulate additional stress to go first.  The other can then pay the same amount to act simultaneously, or more to go before, and there can be a nice little bidding war to see who acts first.  No bid can exceed the size of the Battle Threshold (though the results of the bidding can go beyond the size of the threshold.  I.e. if your threshold is 7, you can accumulate no more than 7 stress in any given attempt to go first.  However, you can bid up to 7, even if you already have 5 stress).  Moreover, no character can act out of turn if his action stress exceeds his Battle Threshold at the time of action.


These two mechanics together already make even a simple swordfight between two evenly matched opponents with no special abilities far more interesting than many RPG fights, as they jockey for position when deciding initiative, and then decide whether to go all-out and exceed the bounds of their threshold, or else conserve some brain-time for defending themselves.