Shield Defense for Dice Neutral Attack Tables

Wednesday’s dice neutral combat table did not include shields, for a couple reasons. One being: There’s just too many ways shields get changed in house rules.

In standard D&D, upgrading your body armor from leather to chain, or from chain to plate, effectively adds +2 to your defense. Keeping your current body armor but adding a shield is half as effective, adding +1 to defense. If a GM prefers the standard approach and is using a d20 (or 4d6 drop 6,) they can either add +1 to the target number or (my preference) subtract 1 from the attack roll to get the same result.

But that’s not the only way GMs handle shields in D&D. Some people think shields should be more effective, giving them a +2 defense. Or they add different tiers of shield. For the flat +2 approach, the GM can just shift right one column, so that adding a shield is just as effective as upgrading your body armor. For shield tiers, just subtract 1, 2, or 3 from the attack roll based on the type of shield.

Another idea for a shield houserule. If an attack roll hits exactly (roll = target number, not roll > target number,) roll 1d6. On 4+ the shield blocks the attack. A GM can also adapt this for shield tiers, with weaker shields only blocking on 5+, better shields blocking on 2+ or 3+. Or keep the target number static (5+) but use different dice types for different shields: 1d6 for bucklers, 1d8 for standard shields, 1d10 for tower shields.

Or another option: merge the idea of a shield roll with Shields Shall Be Splintered. Roll a 1d6 to block any successful attack. If the result is higher than the damage rolled, the attack is block, but if the result is 5+, the shield is splintered, whether it blocks the attack or not.

If the GM is not using 1d20 for attack rolls, but is using 1d6 or 2d6, then upgrading body armor is only “worth” 1 point of defense. If you modify the target number or the attack roll, this means that a shield will be just as effective as upgrading to a heavier class of body armor. If that’s not what you want, you should use one of the “shield roll” house rules, or use another houserule, like reducing damage.

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The Secret of Descending AC

Screw it, I’m going to add two new armor types to the way I handle armor. But before I explain that, let’s take a detour and talk about descending armor class, since I have avoided it for a while.

There’s a little secret buried in the original AC system, one I’m not even sure Gygax and Arneson thought of. Gygax certainly seemed to have stepped away from the secret when he added negative ACs and a few other things. But it all stems from thinking about the AC numbers. Why does AC run from 2 to 9?

You can multiply AC by 10 to get a rough comparison of vulnerability.

A theoretical AC 10 would be 100% vulnerable. But 100% vulnerable sounds like “automatic hit” to me, and AC 10 definitely wouldn’t work that way in practice for the standard D&D combat system (chance to hit AC 9 is +1 compared to AC 8, +2 compared to AC 7, etc.) Same deal with AC 0, which would be “0% vulnerable” or completely impossible to hit.

It was this sort of thinking that lead me to abandon the modifiers “to hit” for things like cover or aimed blows and instead just divide the AC number by 2 or 3. For 50% cover, or aiming at someone’s arm or head, I’d use AC 5 or actual AC, whichever is better. For a smaller target, like the heart, I’d use AC 3. For a truly tiny target, it would be AC 1.

Now, I’ve been using a system in my monster stat blocks and dungeon modules for a while now where I abandon AC numbers completely and use the descriptors No Armor, Light Armor, Medium Armor, and Heavy Armor instead, so people who use either descending or ascending AC, or another system entirely, can all use my materials. But I still think of them as AC 9/7/5/3 behind the scenes, so I’ve been mulling over whether to do something about AC 1 for a while. And as I worked on some new material recently, I finally went for it, and created a new armor type: Extreme. There’s no wearable armor equivalent. It’s reserved for enchanted, magical, or demonic creatures.

There’s one other armor type beyond that… not AC 0, technically, for the conceptual reasons I previously explained. It’s the armor type I’m calling Abstract, because it’s used for things like “attacking someone’s will to live”. I’ll be using it eventually when I tackle psychic combat. Base chance to hit is 1 in 20.

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Ceremonial Magic Robes

Obviously, I'm behind on posting, but I may have some things in the near future. For now, here's an idea for riskier magic.

Casting a spell has a chance of attracting unwanted attention from beyond. Roll 1d6 any time a spell is cast: if the result is lower than the spell level, an angry spirit appears to attack the caster (optionally, the number rolled is the number of spirits that appear.) Thus, 1st levels spells are usually safe, 2nd level spells have a 1 in 6 chance of summoning and angry spirit, and higher level spells are riskier.

A set of ceremonial magic robes reduces this problem. These robes cost three times as much as Leather Armor and provide equivalent protection against spiritual attacks only. They provide no defense against physical attacks, and mundane armor provides no defense against spiritual attacks. Furthermore, no roll is required for spells of 3rd level or less.

Better quality robes may exist. Robes that act like spiritual chain mail cost three times as much as regular chain mail and eliminate the need for rolls when casting spells of 5th level or below. Robes that act like spiritual plate cost three times as much as ordinary plate armor and change the roll to 2d6, which makes high-level spells safer.

Troll Questions: Armor Class

Another post on the top ten troll questions.

(3). Ascending or descending armor class?

Descending, definitely. I've talked a lot about this, about how ascending AC systems tend to treat AC more as a number, with the implication that there is no upper limit to that number. Also, I have some tricks based on the supposition that armor class is descending, which wouldn't work if I switched to ascending AC. In other words, ascending AC is vastly inconvenient for me. That's fine, because Target 20 actually eliminates the need to switch to the d20 SRD standard method; it gives you the exact same benefits, with descending AC, as the d20 system does, with ascending AC. I already have the descending armor types memorized, and they work with Target 20. I have the option of going with what's easy, or going the more difficult route of memorizing ascending AC types (or converting every AC as I encounter it.) A whole lot of work for no extra benefit.

For people who started with ascending AC, the situation is reversed. Why should they switch to descending AC, even to use Target 20, when that will mean memorizing which types of armor match up with which AC?

It doesn't matter how "logical" a method is. Sometimes, it creates a cascade of other problems for players used to doing things a particular way. If you know something backwards and forwards, you'd be a fool to switch to a new method.

Shield Block Approaches

I ran a poll on both RPGNet and The RPG Site about how people handle blocking with shields in TSR-era D&D and D&D clones. I asked about three basic approaches:

1. The standard rules (having a shield changes your defense rating;)
2. Shields provide Damage Resistance;
3. Shields Shall Be Splintered! (Or some variation of it.)

I tried to make it clear that I wasn't asking about actual numbers, but general procedures, so changing the AC modifier for shields or having some shields be worth 1 AC step and others 2 AC steps still counts as "no change to the standard rules," but in retrospect, I should have not used that phrase "no change"... nobody seemed to get what I was asking. I saw the three options representing three general approaches:

1. Modify the attack roll;
2. Modify the attack result (damage;)
3. Undo the attack.

Here in OSR blogland, Shields Shall Be Splintered seems awfully popular. On the other hand, I'm always seeing people arguing that shields (and armor in general) should reduce damage instead of making the defender harder to hit. But on the other other hand, Shields Shall Be Splintered is, in some ways, a very "meta" rule, requiring some retconning of a supposed hit into an effective miss by sacrificing a shield. That seems like something many people in traditional gaming rail against.

I was wondering if my perceptions were skewed by selection bias, or if people really were more accepting of undos or rerolls than I thought. So, the polls. The sample was small, but somewhat consistent: the majority (73% on RPGNet, 52% on The RPG Site) stuck with the standard rules or close to it, but Shields Shall Be Splintered! beat adopting a damage resistance approach. In fact, there was only 1 vote for damage resistance on each forum.

It was sort of surprising that more people answered the poll on The RPG Site than on the supposedly-larger RPGNet, but perhaps that was because I put "OSR/TSR-Era D&D" in the title, and RPGNet has a policy of banning most of the people who play non-WotC D&D.

Ring, Scale, Chain

In the past, I may have said something about making either ring or chain (I forget which) more vulnerable to missiles, or something like that. In yesterday's post about studded leather and splint mail, I inadvertently suggested that ringmail, scalemail, and chainmail provide identical defense. Part of this is because, from what I read in the Ffolkes book on armor, it looks like there wasn't much difference between the protective value of different kinds of mail, just in the quality of the armor. Older mail seems to be mainly scale or various kinds of ring arrangements (including banded mail, which I never knew was actually just a way of arranging rings, scales or splints.) Chain is a more elaborate (and expensive) way of doing the same thing, but making the end product sturdier.

Specifically, ring or scale connect their metal bits with leather or to a cloth/leather garment, while chain is interwoven links that don't use any other material than the metal itself (although it has to be worn over a quilted or leather garment to avoid discomfort.) Therefore, attacks that rot or harm leather (engulfed in flame or ochre jelly) can ruin a suit of ringmail or scalemail, but will leave chainmail basically unharmed.

Spear and Shield Summary

Time to summarize some thoughts on the great debate about using a weapon length/AC swap rule for melee weapons, but excluding spears from that benefit, as well as the +/-2 modifications for using certain weapons (including the spear) against a shield. In case anyone missed some posts in the debate (or the comments on those posts,) here are the links:

1. My thoughts on modifications to combat, and the responses
2. My follow-up and brief second follow-up
3. Charles Taylor responses about spears, shields and axes, and weapon reach

(Charles also has a post on confined spaces, not quite related to this exchange, but worth looking at. I had some thoughts on confined spaces a while ago, but forgot what I came up with, so I'm waiting a while to see if I can remember...)

Now, a great deal of the disagreement involved differences in the way we use words (like "block",) and possibly also they way we abstract combat (I'm a confirmed one-minute round, one roll to summarize the results of many combat actions GM, which might not be what Charles is doing.) Also, Charles seems to fall back on examples drawn from one-on-one challenges, whereas I'm thinking more in terms of melee in an enclosed space. This is why I talk about advancing/retreating and Charles talks about circling your opponent, which in my mind is something you'd never do if you're putting yourself between a crowd of goblins and your weak magician comrade. But we can skip all that; we're more concerned with the two main points of contention: (1) Does allowing two-hand swords to treat plate as AC 5 or 6, but not extended the same benefit to spears make the spear useless, or weaker than it should be? (2) Is the +2 bonus for ax/flail vs. shield illogical?

First, I'll respond to # 2, the easier point to deal with. The +2 for ax/flail, -2 for spear/bow vs. shield is, as mentioned, derived from an analysis Simon Bull did of the weapon vs. AC tables in Eldritch Wizardry and the AD&D PHB to simplify them. That's what my weapon-length swap rules were about: my own way of simplifying those tables, to produce nearly the same effect. So, although it does introduce a quirk where you can drop your shield when faced by an ax-wielding maniac and improve your odds, it does remain truer to the source. Note, though, that both I and Simon use Shields Shall Be Splintered, so the best response would not be to drop it immediately, but to sacrifice it to the first ax blow. And that's assuming you're only being attacked by people wielding axes, and not a mix of weapons.

(Incidentally, I've been reading Will McLean's blog about medieval matters, mostly because he posts excerpts of actual historical descriptions of armored combat. One of the things he found was that, historically, shields tended to be discarded after the first blow or two, mainly being used to block a thrown spear, very much as the Shields Shall Be Splintered usage would suggest.)

Anyways, Simon and I discussed the +2 ax/flail implication and came to the conclusion that reducing the mod to +1 (and -1 for spear/bow) wouldn't be too far away from the effects of the original weapon vs. AC table, but would correct this problem when using the tradition +1 defensive bonus for a shield (he actually uses a +2 bonus for the shield as a house rule, so he wouldn't have that illogical quirk.)

So, #2 is dispensed with: quirk eliminated. Now, back to #1. It's important to remember that, even if swords of 4 feet or longer get a benefit that the spear doesn't, the spear isn't any worse in terms of the attack roll than many one-hand melee weapons, and it's considerably better than a short sword when you take into account:

1. the reach,
2. any two-handed weapon bonus,
3. the fact that it can be used one or two-handed, even with a shield,
4. the fact that it can be thrown,
5. the fact that it does double damage on a charge,
6. the fact that it can be used from the second rank,
7. the fact that it can be used two-handed up close to block or push back an opponent.

In fact, spears are pretty versatile and ought to be considered as a second or third weapon option on an expedition. Just because it can't be used as an all-in-one answer to every combat situation doesn't mean the spear has been "nerfed".

In particular, I'd like to point to my comment about a spear being a "knife on a stick". There's two reasons I said that (not counting the fact that I'm not the first person to say that.) One is: the weapon-length/AC swap idea is basically using weapon length as a stand-in for weight of a melee weapon and the size of the danger zone. The other is: like a knife, the spear is best when it is aimed at a vulnerable spot ... but unlike a knife, the reach of the spear allows you to stab at an eyeslit or a weak spot in armor from a safe distance, perhaps even as the first blow in combat.

So, although Charles is definitely going to continue doing things his way and I'm going to do them my way, I hope he sees now that I'm not planning on making spears irrelevant.

Weapon Length vs. Armor Class

A quick little idea to discuss: what if, instead of a Weapon vs. AC adjustment table or various other suggestions like that, we said "when attacking an armored opponent with a weapon, you can substitute the weapon length, in feet (dropping fractions) for the armor class, up to the max weapon length/AC of 9"?

Percentile AAC

I'm not a fan of ascending armor class. Too much emphasis on high numbers and number-jiggling.

And I'm not a fan of percentile systems. Too fine a granularity for me.

So, of course, after reading Randall's post that mentioned a percentile combat system with AAC, I thought of a way to do this. Haven't read the magazine article, so Randall will have to tell me whether I've accidentally copied the system he read about. Otherwise, this is free to anyone who cares about such things.

An unarmored target is AC 50.

Light (leather) armor adds +10.

Metal/hard armor adds +20 or +30, depending on whether the metallic bits are small or large. Halve the value if it's rusty.

A shield adds +5. Optionally, you can buy a +10 tower shield.

A simple leather cap is assumed to be included in any armor. A metal cap/open helm adds +5, a full helm +10.

Roll percentile dice and add your hit points to the result. If it's higher than the AC, you hit.

Ranged attacks add Dex, but a moving target adds Move to AC.

Opponents who chose to do nothing but dodge add their Dex to their AC.

The larger point differences of a percentile AC system means that you can add armor degradation. Every 00 rolled subtracts 1 point permanently from the target's AC. This happens after the test to hit, and 00 isn't an automatic hit, so super-high AC means you might take a hit that does no damage to you, but it slowly ruins your armor. The defender can pick which piece (shield, helm, body armor) is affected.

When you find or buy armor, on the first attack, the GM determines the armor quality: take the first digit of the attack roll and subtract the second digit to get a +/- 1 to 9 modifier to the armor's quality.

Ffoulkes

For those who didn't see this link elsewhere: Project Gutenberg now has "Armour & Weapons" by Charles John Ffoulkes, complete with images. This was one of the primary references Gygax and Arneson used for D&D.

What AC Is Magic Armor?

Ian asked on the post about fixing armor to make it less focused on raw numbers, "Why not just have all magic armor/shields automatically grant AC 1?" I assume he just meant armor; allowing a fighter equipped with just a magic shield and no other armor to have a better armor class than plate and shield seems kind of extreme, and since bonuses don't stack, no fighter with a magic shield would be so foolish as to wear armor. But even just talking about magic armor, there's a couple reasons why I wouldn't make magic armor a flat AC 1:

1. The defensive value doesn't stay the same. I proposed the change to magic armor in tandem with a change to magic weapons; magic armor thus doesn't always provide the maximum protection.
2. The defensive value isn't always the equivalent of AC 1. The 3LBBs only have magic plate, but magic chain and magic leather armor could easily show up. Players expect that they exist.
3. Plate armor, even magic plate, is not AC 1. I believe in hard armor classes with no overlap; plate armor is AC 3, even if it is magical and has a defensive bonus. This is especially relevant for those using weapon vs. AC rules, since those depend on the real armor class, not the equivalent due to bonuses.
4. I'm trying to get away from the numbers. Lately, I've been referring to Light, Medium, and Heavy armor instead of AC 7, AC 5, and AC 3. This is so that those who prefer ascending AC can use their own numbers with stuff I've written up.

So, I'd rather say that magic armor provides a 2-point defensive bonus against mundane weapons, since that covers either ascending or descending AC systems as well as different varieties of magic armor.

Armor Sidenote

There's another interesting little rule buried in Monsters & Treasure. The bonus from magic armor is supposed to be subtracted from the attacker's hit dice. Now, most people assume this is a subtraction from the d20 roll, or an equivalent adjustment of the armor class. But that's not what the original rules are saying at all; a monster's attack capability is based on its hit dice, and you are supposed to reduce this if a monster attacks someone in magic armor. In many cases, this is a leftward shift on the Monster Attacking table, but a 6 HD creature, for example, has the same chance of hitting an opponent in +1 armor as it does against an opponent in mundane armor. Really beefy monsters -- 14 HD or more -- aren't phased by magic armor in the slightest.

Of course, I've been using Target 20, so I haven't noticed this effect before. I'm wondering if it's worth it to try to implement the same effect outside the table.

Magic and Armor, Rules As Written

No, I'm not going to discuss mechanical effects on spell casting, as I have before. Instead, I wanted to point to this comment from Frank Mentzer in a thread on Dragonsfoot:

"Where in any D&D or AD&D rulebooks does it place any restrictions at all on magic use (devices or castings) based on your attire (e.g. armor worn, baggy pants, shorts, types of shoes, etc)?
And if the answer to my question is "nowhere", where the heck do these misconceptions arise?" 

It's a subtle point. The rules do restrict the armor a magic-user can wear, but don't say that magic itself is affected by armor. Men & Magic doesn't even say a magic-user can't wear armor, only that they can't use magic armor and weapons, which is why I rule that magic armor and weapons act like their mundane equivalents unless used by a fighter or cleric.

The reason why some of us also make armor restrict magic is because we like the image of robed magicians and want to emphasize armor as a feature of fighters (and clerics.) Restrictions on magic use while wearing armor helps reinforce the stereotypes. I would say, though, that a magic wand is not restricted in the same way, as long as the magician isn't wearing gauntlets.

What To Do With Descending AC

I've said before that I prefer descending AC, starting at AC 9 for no armor and going down to AC 2 for plate and shield. So I won't go over that again. But I thought I'd toss out some ideas on what to do with descending AC numbers, besides determine chance to hit.

Movement: Ignoring shields and encumbrance, round the AC of armored characters to the nearest power of 3 and add 3 to get the base move.

Thief Limitations: If using Dex bonuses for thief skills, only allow the bonus if Dex <= AC x 2.

Combat Evasion: Compare the lower of AC, Dex, or movement rate to the opponent's AC, Dex, or movement rate; the side with the higher score can withdraw out of reach before the other side can strike.

Cutting Wounds: If you are using 1d6 damage rolls and want to treat cuts as different from bruises (requiring 1 turn to bandage,) add opponent's AC to your damage roll; on a 10 or more, the opponent was cut instead of bruised.

Stunning Blows: On the other hand, unarmed attacks can be treated as being less likely to do real damage. Add opponent's AC to damage roll; damage (1-6) is real on a 10 or more, but on a 9 or less, it's treated as subduing damage.

Hard Armor Classes

There was a stray comment in a blogpost a few days ago about revealing the armor class of monsters to players during a fight. My initial reaction was to think that I wouldn't normally do this, but then I started to reconsider, in light of the way I think about armor class.

D6-Only Weapons: Damage Types

Over at Bat in the Attic, there's a post about a simplified weapon vs AC system, which has helped me clarify in my own mind the next step in this series about how to make weapons distinct without changing the damage. As Rob Conley notes, a threefold division of weapon damage types is pretty much standard in RPGs these days. He uses this simplicity to add up to three modifiers to each armor type, which is pretty compact.

Of course, I only have three basic armor types, so it's just as easy for me to describe weapon vs. armor from the perspective of the weapon.

• blunt weapons are the default; they have a +1 advantage against rigid and semi-rigid armors unless made of a weaker material than the armor.
• edged weapons have a +1 advantage against nonrigid armor and can damage armor made of weaker materials.
• piercing weapons have a +1 advantage against semi-rigid armor made of rings or links and against nonrigid armor, but do no substantial damage to armor (they can make a hole, but this doesn't give an attacker a future advantage as more serious damage would.)

Under this scheme, chainmail, ringmail, banded mail and scalemail are all semi-rigid armor (type 1, equivalent to AC 5,) but ring and chain have a disadvantage against stab attacks, chain has an advantage against edged because of interwoven links, and banded mail has an advantage against edged and piercing (although plate is still better than all.)

Armor Class Interface

A couple passing comments Jonathan Tweet made about the low design quality of old school games, in particular a comment about how ascending armor class scores are clearly better than descending scores, started a minor reaction among old school bloggers. (Fortunately for Tweet, a doom-and-gloom post has directed attention away from him to some extent.) I don't want to attack Tweet directly; who cares how he feels about descending ACs, as long as they work for the people who use them? The real question is whether ascending ACs are "clearly better" than descending ACs, and how this relates to a broader issue of interface design.

A couple years ago, I read The Design of Everyday Things by Donald Norman. It's about the psychology of the design of practical everyday items, like door knobs and door handles, water faucets, telephones, and car dashboards. One element he addresses is affordances, the components of everyday objects that enable us to act on them. There's a psychology to the shape of active components: buttons want to be pushed, levers want to be pulled, knobs want to be turned. One bad design mistake that rises again and again is making the shape of a control component suggest one kind of action -- turning, for example -- when the control requires a different kind of action entirely, like pulling. Another element the book addresses is the way the interface, especially the part that reports the results of actions, must either match the mental map of the people using the interface or give enough clues to let the users figure out the correct mental map. You don't place two buttons one above the other, but map the interface so that the top button lowers the temperature or volume; it's confusing.

The book made me rethink RPG design and inspired me in several ways. For one, it inspired my various mechanics that use the position of dice rolled on a character sheet or "dice map" to generate results. For another, it made me reconsider whether RPG design should be mainly about game design or interface design. But it's also been useful in considering why different games take different approaches to generating a particular result, and which approaches are best under which circumstances. If an ability score table notes plus and minus modifiers, the player expects to add and subtract these modifiers to and from something; it's an affordance. If you see a dice notation like "3d6", you expect to roll the dice.

OD&D had descending armor classes, 3e/4e have ascending armor classes. Both have you roll a single die, modify the result, and compare that to a target number. Which is better? From the new school perspective, it's better to use the AC as your target number directly than to look up a target number using the AC as a guide, so for a roll-higher mechanic, ascending ACs make more sense. But it's been pointed out that an old school shortcut is to add the AC directly to the die roll, along with a level modifier, and beat a fixed target number of 20, which is actually a little easier than having a variable target number. Clearly, math isn't the issue.

What's being neglected is the different mappings. In OD&D, the armor classes were originally fixed, non-overlapping shorthand descriptions of armor types. There were no modifiers to AC: Chainmail +1 adds +1 to your opponent's target number to hit, not to your AC. There were no AC 1, AC 0, or negative AC monsters. Since there were no negative ACs, and since the target numbers for the tables were derived from subtracting AC from 20 and modifying for character level, it made more sense to use a descending AC, especially if you used a house rule that made movement rate equal to AC. Under an OD&D "to hit" table approach, almost all modifiers are included in the table already, so there are only three things to be added or subtracted from any number in combat:

1. magical weapon bonus (+1 or +2,) added to the die roll;
2. magical armor bonus, added to the target number;
3. situational bonus of +/- 1 or 2, based on a DM's ruling.

In a sense it would have been better if old school ACs were letters rather than numbers, since having an AC 2 immediately made players imagine an AC 1, which lead to modifications in the game that eventually lead to THAC0 and tables with the repeated 20s. It was AD&D that increased the complexity and confusion by dissociating AC from actual armor type and treating AC as a number that could be modified, or a scale that could be extended in either direction. Once that was done, then clearly it made more sense to use ascending ACs as a target number, since that has a better mapping than positive and negative ACs used as a table look-up.