I’ve mentioned “attack value” a few times so let me explain what it is.
It’s for when you’re using the common house rule (it’s been seen, among other places, in the 3e Unearthed Arcana book) that the players roll to attack monsters and roll to defend from monsters, and the monsters have static values for defense and attack. There’s still the same amount of rolling total, so you don’t change any outcomes, only the feel of the game.
The rule as published had the wrong math, they subtracted on the wrong half of the equation, so here are the numbers we use:
For opposed rolls player-vs-player, have both players roll when fighting. Defender wins ties. In PvP spellcasting, the attacker always has an 8 so only the defender rolls. In PvM opposed rolls for ability checks or what not (hello grappling) I’ve often had monster just get a standard 10, but that does change the probs compared to both sides rolling so it’s often better to just do that.
We’ve used this for many years, we started using it gradually (players would have both a normal AC and a “defense roll” listed) but then went over to using it all the time. Even now, eight years of using it all the time, I don’t know what I think about it.
It makes them handling the game items (dice and numbers) all the time at the expense of the mood and tension of the diegesis. Sometimes I wonder if the other way around wouldn’t’ve been better. The players only focused on describing their actions. I even wrote a ruleset based on that idea.
We use it in combination with Oh, Injury! and an interwoven initiative system and it’s been synergic with them. They swing at you, you try to parry, but their attack was a feint (you didn’t make the defense check), so you exert yourself (you pay hp) to twist yourself to the side to dodge their blade, and then you follow up with a swing of your own, and it lands and fells them. It’s pretty great, and all with the same underlying math as D&D, meaning that you have access to hundreds of well-playtested monsters and dungeons.
It goes without saying, but defense checks, just like momentum attacks and the golden opportunity strike from Oh, Injury!, don’t cost any actions in the initiative order. This is great, makes those six seconds a round take really frantic.