Stuff you can do with an ascending AC and attack bonus-based combat paradigm
Taking a break from the Monsters A to Z for some pondering on what you can do with some new old-school friendly combat mechanics.
One of the strongest signs that Old School gaming is not simply about nostalgia is the extent to which old schoolers have embraced ascending Armor Class, in conjunction with class-based attack bonuses, over the old descending-AC-and-attack matrix or THAC0 system. It doesn't just streamline the math and eliminate a whole layer of fiddliness, though, as much as those effects are to be hailed. Within the ascending AC and attack bonus framework, you can do some pretty cool things that would have required some real mental gymnastics in the traditional system. The magic of this approach really lies in the use of an attack bonus stat rather than lines and columns in an attack matrix, which allows everyone to use the same target number for the same target.
To illustrate the point a bit more clearly, consider a 5th-level fighter and a 1st-level magic-user in B/X attacking a target with AC 5. In the olden days, you'd look at the attack table, finding the column for AC 5 and the rows for Fighter 4-6 and Magic-user 1-5. This would tell you that the fighter needs a 12 to hit and the magic-user needs a 14. THAC0 is just doing the same thing from a different angle. The fighter has a THAC0 of 17 and the M-U has THAC0 19. Subtract the target's AC from the THAC0 and you get 12 and 14.
Using the newer but simpler system, both characters need to achieve a total of 14 or higher on their attack rolls to successfully attack a target with ascending AC 14. The fighter's advantage comes not from a lower target number but from a higher attack bonus, which is recorded neatly and concisely on his character sheet. One target number for anyone attacking that opponent; one attack bonus number per character or monster. Dead simple.
Using the exact same principle, you can set a target number for other things besides the most elementary goal of scoring damage against the target, and because of the attack bonus mechanic, you can use the same target numbers for any class and level while preserving the advantage of those who are supposed to be more skilled. The most obvious such target number is 20.
Multiple Attacks
Multiple attacks for characters have always been a bit wonky in D&D, in that they have traditionally been granted at specific level thresholds. The result is that you get a big power jump at those levels. (B/X did not have a multiple attack rule for characters, but its spiritual successor BECMI allowed two attacks for fighters at level 12, three at level 24, and four at level 36.) AD&D tried to smooth the jumps out somewhat with those clumsy three-attacks-per-two-rounds monstrosities.
A Target-20 threshold for a second attack solves the whole mess rather nicely. If, say, a fighter's attack bonus increases by +1 per level, as it does in an AD&D-style progression, this means an extra 5% chance per level of any attack roll triggering a second attack roll, instead of leaping suddenly from 0% chance of a second attack opportunity to 100%.
Damage Reduction
Ever considered having armor directly reduce damage instead of making the target harder to hit, but want to allow for critical hits that bypass damage reduction? Set the "ignore armor" threshold at 20, and the combatants with the best attack bonuses will trigger it proportionately more often than the less-skilled, instead of everyone having a flat 1-in-20 chance regardless of skill, as obtains in traditional Nat-20 critical hit systems.
Defensive Fighting
How about allowing a combatant to use his combat skill defensively? Subtract the defender's attack bonus from the attacker's, and apply only the difference to the d20 rolls. If a warrior with a +2 bonus is in melee against a warrior with a +4 and decides to defend, the second warrior attacks at only +2, and the first at +0. If the second warrior chooses to defend, then he attacks at +0 and the first warrior attacks at -2. This synergizes well with the multiple attacks option above; by using his attack bonus defensively, a combatant can significantly reduce not only his chances of being damaged in the first place, but also the odds of his opponent tripping the Target-20 threshold for extra attacks. This would make scenarios like fighting withdrawals and holding on until help arrives much more tactically useful.
Special Maneuvers
How about tricks like disarming, called shots, cutting straps, and whatnot? You don't need pages of special rules; just Target-20 it.
Bring It All Together
Any or all of the options above should mesh well together, too. Let the player decide what effect to apply if the roll trips the Target-20 threshold, but you can only choose one. You might choose a second attack roll to maximize damage potential if the target is fairly squishy, or go for bypassing damage reduction against a heavily armored foe, or some other effect if you have something in mind other than brute damage. The DM could require the desired effect to be declared before the roll, but it's easier just to allow the choice after the fact, and avoid eating up precious table time with declarations that turn out to be moot if the roll isn't high enough.
Opposed Rolls
Forget Target-20 for a moment, and imagine a contest in which only one combatant of a pair can gain a particular result or advantage. Opposed rolls are quick and intuitive too: instead of requiring a total of 20 or higher, it's simply high total wins. Among other things, this strikes me as an excellent way to model fighting with weapons of significantly different reach. A fighter with only a dagger trying to attack another fighter holding a spear can close and stab -- if he wins that opposed roll to outmaneuver his opponent and duck inside the reach of the spear. Conversely, once the dagger-wielder gets inside his reach, the spear-fighter can once again put distance between them by winning a subsequent opposed roll -- AND there's no need to make extra rolls, since these opposed rolls are just the normal attack rolls you'd be making anyway.
There's probably a lot more you could do with this slick, streamlined attack mechanic. Feel free to drop suggestions in the comments.
I want to understand what you mean by target 20 here. Do I read it correctly that if your attack roll + modifiers = 20+, then cool stuff, like extra attack, happens?
ReplyDeleteYep, you've got it exactly. (Sorry for the anonymous reply. Google doesn't seem to want to play nice with my browser lately.)
DeleteI am using brave browser and have to disable "shields" to use my account on blogspot these days.
DeleteI've been using Libre Wolf, and I cannot for the life of me find any setting that makes a difference in that regard. Even stranger, sometimes it will let me sign in, and I haven't done anything at all different. Maybe I ought to give Brave a go, if the settings are more intuitive and easier to change.
DeleteI really like this post, and have come back to read it several times. I wonder whether you'd clarify your final example about combat between fighters with different reach (spear vs. dagger, e.g.). I think I lost the plot there a bit - it sounds like they're making an opposed to-hit roll (both acting simultaneously?). Could you walk through an example of what you mean there? Thanks!
ReplyDeleteGiven your recent post on combat without initiative, now I'm wondering whether "simultaneous action resolution" is exactly what you meant. :-)
DeleteI think you're correct that it would work best with simultaneous resolution, a factor I hadn't consciously considered. You may have already sorted things out, but I'll try to clarify anyway, for anyone who might still be scratching their heads over what I meant by that mess up there.
ReplyDeleteWe'll take the example of a fighter with a spear vs. one with a dagger. I think it's safe to say, at the first clash, the guy with the longer reach has an advantage over the one with shorter reach. He could plausibly hold the dagger fighter at bay, keeping him from even getting close enough to land a blow. Each fighter makes an attack roll as usual, and we use the rolls in two ways: the traditional way, comparing the rolls to AC to see if damage is caused, and comparing them to each other to see if the advantage shifts.
Here's the interesting bit: the fighter who starts the round with the advantage can always deal damage if his attack roll beats the other's AC, but the other one can only deal damage if his roll beats the opponent's AC AND the opponent's attack roll. This represents the need to get past the weapon with long reach in order to strike.
Let's say our fighters both have AC 15 (ascending). They meet each other in melee combat, and both roll their attacks. Spearman gets a total of 17, and Dagger gets a 16. Spearman does damage to Dagger because he has the advantage (greater reach) and his roll beats Dagger's AC. Dagger's roll does beat Spearman's AC, but because his attack roll was less than Spearman's, he's not able to slip past that menacing long spear to actually strike and make it count.
Next round, Spearman rolls a 6 and Dagger gets a 15. Spearman's roll is a fail all around. Because Dagger's roll beats his, Dagger is able to close the distance, getting nose-to-nose with his opponent, and because his roll hits AC 15, he does damage too. (If he had rolled less than 15 but greater than 6, he would have been able to close the distance, but not deal any damage.)
Round three, and Spearman is now trying to fight with a long, awkward weapon at very close quarters, so the situation is reversed. Now he has to beat Dagger's roll in order to even qualify to do any damage. He rolls a 19 and Dagger gets a 16. Both do damage to each other, and Spearman manages to shove Dagger away, restoring the original advantage of his longer weapon. If Spearman had rolled a 15, which ordinarily would be enough to do damage, he would have failed to restore his advantageous distance and so fail to do any damage because of his spear's clumsiness in close quarters combat.
Thanks - that is helpful and makes sense (and looks cool). I think I like it - but I am pausing a bit, wondering whether this might lead to too many headaches in an engagement with multiple combatants ... (Ok, so I'm being attacked with two guys with spears, and I've only got a hand-axe, but my comrade here is helping out with a halberd, guarding my right flank...). On the other hand, I haven't thought that one through, so maybe it's much easier to resolve still with simultaneous resolution than I'm thinking.
DeleteThanks for spelling it out in more detail!
It definitely still needs fine-tuning and playtesting. You've put your finger right on one of my big concerns, that of multiple combatants. I'm not sure how to resolve it yet. Maybe fighters can hold off a number of opponents based on a function of their level, while other classes are a 1-for-1 basis only, and any in excess of that get through and attack without hindrance. I dunno. Stuff to ponder. In any case, I probably wouldn't even bother with any of it unless the disparity in weapon reach is pretty big, e.g. short sword vs. normal sword or dagger vs. short sword doesn't qualify. It could be really handy if your fighter is trying to fend off a wild boar or something, though.
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