I must create a system, or be enslaved by another man's. I will not reason and compare: my business is to create.

- William Blake

Saturday, June 03, 2023

Weapon versus armor - from AD&D to B/X

As you might know, I'm into B/X (using my own clone, and also frequently using modules from other basic systems), but I have been reading lots of AD&D lately.

In the last few days, I've been looking at the weapon versus armor table in AD&D. 

Now, according to Delta's blog, the weapon versus armor table in AD&D contains mathematical/revision errors. It is a simple "lost in translation" mistake. I've heard some good arguments saying that there is no error (i.e., the revision was done on purpose). But I think he makes a good point. Go read it and decide for yourself.

In any case, I also think there's cool stuff to learn from both chainmail and AD&D. And this is what matters to me. 

[BTW, Delta - one of the best old school D&D bloggers out there IMO - has done all the hard work putting this stuff on a sheet. I'm only playing with the numbers, and literally adding some color. Any mistakes you find below are probably mine, however - please let me know in the comments].

In chainmail, to hit someone in plate and shield (AC 2 in AD&D) with a dagger, you'd need to roll 12 using 2d6, for example. A 2h-sword would only require 7.  I added and "average" column to compare the overall effectiveness of each weapon.

Notice that green/blue means good (chances of hitting), red means bad. The spear is a "bad" weapon against armor on average.

If you calculate the chances of hitting with 2d6, you'll find that rolling 12 happens about 3% of the time - while rolling 7 or more happens about 60% of the time. 

This means the 2h-sword is TWENTY TIMES better than the dagger against plate and shield - but if your target is unarmored, they are nearly identical! 

Likewise, the mace is about FIVE TIMES better than a regular sword against AC 2, but the sword is a bit better against unarmored foes.

Notice that all weapons deal the same damage in Chainmail.

Now, let's check the Greyhawk table. It might contain a "translation error", but this doesn't matter for our purposes. There is no perfect way to convert from Chainmail to D&D, for various reasons. What we are doing here is looking at certain tendencies and making generalizations (e.g., "maces are good at defeating heavy armor, daggers are terrible for that unless the target is prone").

These tables show that:

- Almost all weapons are good against unarmored and bad against plate and shield; i.e., armor is even more important than AC would indicate (on average, there is a 10-point spread between AC 9 and AC 2).

- On the other hand, most modifiers are positive, which means you're hitting more often against anything but plate. 

-  The biggest difference is against low ACs. In practice (because THAC0 and statistics), this means choosing the right weapon could double or triple your damage against heavy armor, but barely matters  (damage output raised by less than 20%) against unarmored foes.

- Heavy and unbalanced weapons are good against heavy armor, and just better overall.

As you can see this solves a number of issues with B/X weapons, for example. The sword stops being simply the best weapon (1d8 damage), and faces some difficulty against heavy armor. The spear is in a similar situation (long, good against charges, but bad against armor). Big weapons, such as the lance and 2H sword get a well-deserved boost. The hand axe is no longer simply cheaper and better than the mace.

In addition, it makes wearing armor more relevant. This is also a much deserved boost to plate armor, which is heavy and restrictive. Plate gives you great protection against a sword or dagger, maybe making you invulnerable (unless you're prone - see below!).  

While this is much simpler and a bit more sensible than the AD&D table, it is still a bit fiddly for my tastes. Of course to see the whole picture, we'd have to consider speed factor and space required - which is much worse. And we'd also need to consider variable weapon damage, a popular rule in B/X and basically every version of D&D.

But maybe we can extrapolate some cool ideas from here? 

Let's see... 

The easiest way of simplifying this is just giving a bonus to hit to certain weapons (from 0 to +2 ti avoid negatives). Instead of calculating it, we should judge on a case by case basis.

Or we could get more detailed.

Light, balanced weapons (dagger, hand axe, spear, short sword, club) have a hard time against heavy armor. Let's say, -1 to hit against chainmail (AC 5[14]) or better (but see "daggers and penalties", below).

[Wouldn't it be nice if these lighter weapons gave you a small bonus when backstabbing? Now, the thief can still backstab with a heavy weapon, it is just not optimal. And Chainmail also gives pointy weapons a bonus against prone targets in armor. Neat!].

Heavy/unbalanced weapons (two-handed, with the "slow" tag) are more likely to cause damage: +1 regardless of armor.

I used to ignore the "slow" tag, but maybe give it a -1 to initiative puts things back in the right place.

Everything else is unchanged. I'm not particular fond of "small bonus against medium armor" that some weapons get, and I don't quite agree with some of the conclusions (e.g., why is a 2H sword so much better than a lance against armored opponents?).

This is a radical simplification, that brings me back to an old idea of having a few weapon traits: brutal/unbalanced, fast/balanced, and everything else.

Now, I have so many small problems with D&D weapons that if I were to recreate the list (again) I'd probably start from scratch (or from 5e - at least the weights make sense). But it is fun to see that the original system makes a lot more sense once you actually take the time to understand it - which includes understanding what AD&D got wrong.

Come to think of it, rewriting the entire thing is doable. Not sure if it is worth the effort. Let me know in the comments.



The 1e table
While using the 1e table fixes some B/X weapon problems, it creates issues of its own. A 2H-sword is better against AC 8 than AC 10 (i.e., the unarmored target is more protected!). Same happens occasionally for shields (i.e., having a shield HURTS YOU against a mace).

This is - assuming you're only using a few armor types. Because if you're using all the armor types available, the table becomes impractical, as "AC 5" means different things (sometimes you'll have AC 5 with a shield, sometimes without) - but should ALWAYS protect you more than AC 6, for example.

Still, it is a good place to start.

The 2e table
I feel I should mention the 2e table, which is simpler and more manageable, but still not ideal to me. 

Maybe there's some merit to the idea of separating damage types, but I think we would still have to consider weight/balance to differentiate spears from picks/warhammers, and axes from swords. Maybe add chop (axe) and thrust or impale (spear)?

Looking at this from the armor side - rather than the weapon side - also simplifies things a bit.

Daggers and penalties

I'm a bit unsure of giving any penalties at all. Daggers are already weaker than most weapons because they do 1d4 damage. And, while a dagger should indeed be ten times less effective against plate in a battlefield, players want to use daggers and look cool. 

The sword, on the other hand, gets 1d8 damage. But it is an iconic weapon that I wouldn't like nerfing.

Penalties in general are just bad - they will discourage you from picking a weapon, and could even make hitting an enemy impossible. Players will not care for them in my occasionally "forget" them.

Maybe giving a boost to weaker weapons (such as the mace) is enough.

The "armor bonus" trait

B/X ranged weapons have three ranges: short (+1 to hit), medium (0), and long (-1 to hit). OSE uses this notation: "Missile (5’–10’ / 11’–20’ / 21’–30’)"

Could we do the same with armor for some weapons? E.g. Dagger, "Armor bonus (9/7/5)", meaning +1 against AC 8 and 9, and -1 against AC 5 or better. Seems easy enough if we add it only to a few weapons, but too fiddly if applied across the board. 

I prefer one of the generalizations suggested above.

Monsters and high-level play

One problem of giving weapon bonuses against heavy armor is that powerful monsters will have good armor very often. Should high level heroes ALWAYS carry heavy weapons, since they are expected to face tough monsters?

This problem is not as big as it seems. High level PCs will hit a lot more often against heavy armor anyway, making the difference less relevant. In old school D&D, there are still powerful monsters with not-that-great AC. And finally, one important aspect of making things balanced, I think, is not only throwing powerful monsters at the PCs, but letting them eventually face hordes of minions - which is fun and genre appropriate. 

Still, if you're fighting a dragon, you'd better bring a big sword!

Critical hits

I still think Critical Hits are the best way to deal with these differences. You can just ignore all little details until you roll a natural 20, and then your mace smashes the enemy, despite being worse than the sword most of the time. And everyone loves crits!

I feel Critical Hits are on of those ideas that Gygax didn't include in AD&D because it was too fiddly or "realistic", but in reality could make the game a bit SIMPLER

But let's leave that to another post. I think I could balance all weapons using only critical hits. (We don't need to make them perfectly balance, but we should find at least ONE USE for each weapon). AND maybe I can make speed factor easy. Wouldn't this be cool?

Minimalist OSR + Manual of Arms

All these ideas are being progressively incorporated in my minimalist OSR game, which you can get for free here. All feedback is welcome!

I'm also considering adapting my Manual of Arms books to OSR rules - including weapon versus armor. Let's see how this goes.

Additional reading:


  1. Here's what I wrote about that, just as an point of comparison: https://talesoftheramblingbumblers.com/2021/08/07/fixing-weapons-vs-armor-class/

  2. good homework man. Lots of things to think about in here.

    1. Thank you! I think there is more to find here!

  3. I ended up just giving blunt weapons +2 against heavy armor and brittle enemies (plate, statues, skeletons, etc). Axes reroll 1's on damage and add 1 to the result, and swords have more average damage than either (as is the default for B/X).

    1. Sounds good! The hard part is that whenever you boost maces and axes, the shortsword becomes useless. Sigh, it is a short blanket.

    2. Yeah - that doesn't bother me, because I see that as an apples to oranges comparison; maces, hand axes, and normal swords are all medium weapons. The short sword is a small weapon (you'd compare it directly to the d4 damage club), and no one would use it unless they're a Halfling, who treats all weapons as if they were one size larger (aka wields a d8 sword in 2 hands).

      This size distinction isn't explicit in B/X, though it is in BECMI and many retroclones like BFRPG.

    3. Yes! BFRPG has a decent take on it, love the equipment (EE) book.

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