Fireball Conclusions

What, it's the end of summer this week? Better go out with a bang... In July, I had a sizable series of posts on those iconic and special D&D missile spells, fireball and lightning bolt. One of the things I highlighted was how they have special targeting rules ("declare distance of shot") unlike any other spell -- a legacy of their appearance in Chainmail as analogs to catapults and cannons, in a completely separate category from what are otherwise called "spells" there. See some of those posts: here, here, here, here, here, here, and here. (Leaving out the posts on giant stone-throwing which likewise grew out of the same original artillery rules...). And, in one of those articles, I asked the poll question, "What's the best way to target fireballs?": So that's pretty interesting because I don't think I've ever asked a poll question here that got such a wide range of replies, almost evenly spread over all the available responses. That said, one of the top ones was "Declare target & check 'to hit'... else apply variation"; that seems "right" to a lot of people, even though it appears nowhere in classic OD&D, AD&D, B/X, etc. -- although it was given that way in the more recent 3E. Also tied for the top was "Something else entirely", so I guess fireballs are like opinions... everyone's got their own! Note that pretty much dead last was the option for "Pinpoint any target in range as desired". But with such a divergence in opinion, and a pretty small sample size, for the first time ever I went and cross-posted the same question over at the Dragonsfoot forums, in the hopes of casting a somewhat larger net. Had some good discussion here, and generated these responses: Did that help me? Well, it's not yet double the replies I got on my blog, and the reactions are sort of upside-down from the poll here. Now, "Pinpoint any target in range as desired" came out first (with a narrow majority), but "Declare target & range of shot (legacy rule)" also made a strong showing. So... yet more difference in opinion. One point of analysis is that while this blog is more focused on OD&D and its close descendants, the Dragonsfoot forums are of course dedicated to 1E AD&D, and don't make too much distinction between other stuff they lump together as "Classic". (Not to say that many individual members are not highly knowledgeable about every edition.) And importantly, looking at Chainmail/OD&D you'll be staring at a very explicit "player calls distance on tabletop" rule, while in 1E AD&D this gets submarined into "caster declares distance of shot", which is very easy to interpret as being in-character-flavor and no longer player-skill-mechanic. So the large difference in opinion between visitors, even between OD&D and 1st-Edition sites, is not so surprising. So what to do for Original Edition Delta? Well, this important interpretive issue was one of the last things that I had to "get right" for my upcoming miniature wargame rules, Book of War. And as I thought about it deeply, using the great responses from these polls as fodder, I came to the conclusion that fireballs and lighting bolts simply had to maintain some kind of increased variance, intrinsically baked into their mechanic, for balance and other purposes. I mean -- We all know how crazy-powerful these key 3rd-level missile spells are. In classic D&D, they actually spit out significantly more damage than higher-level spells like 4th-level ice storm, 6th-level death spell, or even 9th-level power word kill, for a caster of the same level (if you crunch the numbers). So what's the balancing factor? The thing that was in the core rules from the inception was the special targeting uncertainty. But on playtesting I found that the direct legacy "declare your distance" was simply far too difficult to succeed at. And more generally, it would be wildly dependent on player skill, such that someone who's spent time practicing their estimation (and thinking to pre-measure the table dimensions, say) would be at a monumental advantage over a newbie player, which was simply unacceptable for the kind of game I wanted to produce (namely: immediately accessible to non-hardcore gamers). Furthermore, that kind of wide-open player-skill mechanic was not something I could estimate or analyze when cost-balancing the different units and powers. So having spent all that time dissecting and thinking about the issue, here's the rule as you'll see it in Book of War:
Roll one die for accuracy: 1-2, 1" short; 3-4, on target; 5-6, 1" long.
Thus, we maintain some kind of variation, which is fundamental to the powerful fireball and lightning bolt spells. It's not outright player-skill, but it is a callback to the original Chainmail cannon rules [CM p. 14, top picture], for example, where all this stuff springs from. Shooting into an enormous formation of troops is easy/automatic. Picking off an individual hero or monster is much harder to accomplish. I've already had some excellent and nail-biting wizard-vs-wizard long-range shootouts with my friend BigFella using this rule. (Side note: This rule is, for its brevity, not unique for the amount of backstage justification that went into producing it. The whole book is pretty much like that.) I'll leave with one keenly important insight. For this mechanic to be justifiable, fireballs must be inherently more variable than archery. Like, based on our normal-curve ballistics insights (here), if you want to shoot an arrow and get within at least 10 or 20 feet of a target, then that's close to automatic at any range, for any trained bowman. Not so with a fireball, even for highly-trained and high-level wizards! So it's not just a matter of "presume the wizard has learned how to shoot a fireball properly"; what we're concluding here is that a fireball is specifically a weapon with such a high rate of variance that it's impossible to be as accurate as anyone is with a bow. They're like the earliest forms of wrought-iron cannons (in so many ways, again as per Chainmail), which were enormously inaccurate compared to other weapons (look up "obturation"). I guess this brand of magic is simply undependable and not-fully-controllable in that way (but it's still generally okay, since it's an explosive area-effect blast, after all). At some point I'd like to come back with exact statistics at the man-to-man level for just how inaccurate a fireball must be (back-reasoning from the simple mass-combat rule). But for now consider this: If landing an arrow or a flask of oil in a particular space is a to-hit against AC10, then doing the same with a more-volatile, harder-to-control fireball shot must be significantly more difficult: maybe AC4 or harder? (Top image by santus, under CC2.)


  1. I think I missed that poll. Less interesting that what I might have voted, however, was that this post made me think that these kind of discussions could lead to multiple variants of a spell in the same campaign. e.g. Bigby’s Fireball vs. Drawmij’s Fireball. Tweak the level and damage for each variant as necessary.

  2. I think it should be significantly harder than AC 4, or that is to say, it should not get easier with experience to the point where an Elf F/M can reliably drop a Fireball on a willow wand.

    I really like the 1" variance, with 1 in 3 chance of precision. That works for me because it's not reliable enough to count on. Here's my example, which happens almost every single session in my game:

    Party, or monsters, advance to melee. PC M-U measures carefully while everyone else is rolling, and declares on his turn exactly where he will drop his Fireball. I don't let the player draw the area of effect, he just marks where he centers it. Most of the time the Fireball blossoms perfectly, killing a bunch of monsters but not singing his fellows. Once or twice the player got the area of effect wrong, both times because he forgot he was indoors and the Fireball had a larger lateral area of effect because of the low ceiling, and the spell hurt some PCs.

    Anyway, this prevents such perfect-aim shenanigans. With this targeting variance rule, Fireball is used strictly as a missile attack because if you aim perfectly you will kill a bunch of your friends 1/3 of the time and you'll miss a bunch of meleeing enemies 1/3 of the time.

    For Lightning Bolt I would give 1d6 for variance left or right at the end of the bolt. 1-2 = 1" left, 3-4 spot on, 5-6 = 1" right. Hitting someone right in front of you will always happen, of course, because the variance isn't that great at the start of the line. (Also I decided a long time ago that Lightning Bolts are all Range Touch and Area of Effect 8", so the bolt starts at the caster's hands.)

  3. I'll be very curious to see how you back-port this to regular D&D play. One of my favorite things about Book of War is how it matches up with D&D, such that it's easy to run huge combats integrated with your D&D campaign. However, I think like me you've given up on having miniatures at the table. Any thoughts on how you'll adjudicate this without physical objects for reference?

    Second question -- is being off by 1" really going to affect your ability to pinpoint a specific target? I mean, with the radius of a fireball at 2", if you aim at an individual and are off by 1", he's still going to get hit. Or were you more referring to the ability to place a fireball so it gets the enemy front-line of a melee, but not the friendly side?

  4. 1d30 said: "I think it should be significantly harder than AC 4..."

    I agree, actually: I said AC4 in the blog post as a conservative initial guess. Somewhere around here I've got notes on the details, but I also think it has to really be harder than that.

    Paul: Good questions. On the first point I do lean on the DMG ideas that sans-miniatures you are shooting/meleeing at a random guy in the blob of enemies. So as a guess I think it will argue against shooting at a melee where allies are engaged, and otherwise as DM I can visualize how big the blog is and figure out whether more or less enemies got caught in the blast. I think.

    On the second point, note that the 1" is at BOW scale, which is zoomed out by a factor of 4; at D&D-scale it's really 4", i.e., twice the radius of a fireball.

    You could almost directly use the Chainmail cannon-variation dowel for this purpose [CM p. 14], which is what I was eyeballing when I decided I liked it so much. Really the rule is just exactly that dowel, scaled and rounded up on the variation.

  5. I'm thinking that 1" short or long is too little, given the 2" radius area of effect -- you're always guaranteed to hit when targeting an individual.

    OTOH, chainmail's optional targeting rule (2 dice, 7=on target, more or less = up to 5" short or long) is way too big a variance for dungeon use.

    So I'd use the chainmail rule, but halve the variance (up to 2.5" short or long). That way there's a chance the target will not be inside the area of effect at all.

  6. Glaurung: I agree, check out what I wrote immediately above your comment. My 1" BOW scale is the same as 4" D&D scale.

  7. "OTOH, chainmail's optional targeting rule (2 dice, 7=on target, more or less = up to 5" short or long) is way too big a variance for dungeon use."

    Begs the question: "why are mobile catapults expected to be used in a dungeon at all."

  8. As a non-English/American i have a silly question: from online sources it seems that '=foot and "=inch. But i have a hard time re conciliating this with given numbers here (is a fireball 5 cm wide and launched at 60 cm? unlikely. So my question, is it often that " is used for feet? how careful should i be when reading about this?

    Also, "Protection from Evil" is a 10' radius and "Invisibility" a 10" radius, is it an error, what are the actual sizes?

    Thanks for any help.

  9. Correction: I just saw the House rules that state: Scale: 1"=5 ft

    I still would appreciate any clarification about the seemingly haphazard use of ' and " in all things D&D, since it is a frequent subject of puzzlement for me, as i'm only used to metric.

  10. Hey Skj -- Great question, and the issue is definitely confusing across different editions of D&D. Indeed, in normal English parlance, (") is inches and (') is feet.

    Original Chainmail had all ranges in inches (") for the purpose of tabletop miniatures, and this was copied into Original D&D. The question then is: What do those inches represent in real-life scale? -- And unfortunately, the answer varies across different editions of D&D.

    Officially, Original D&D stated its scale for listed range and movement was 1"=10 yards outdoors, or 1"=10 feet indoors -- however, you'll find that it's physically impossible to fit miniatures to match that scale. Thus if we use miniatures, we tend to scale the tabletop to something like 1"=5 feet (Moldvay Basic, 3E) or 1"=3.3 feet (AD&D DMG).

    Here's an example: OD&D fireball has a listed range of 24". By the book, this should represent scale 240 feet indoors and 240 yards outdoors. By DMG miniature rules, this would be 72 actual inches on the tabletop. For simplicity, I prefer to instead measure an actual 24 inches on the tabletop (which for indoor D&D I call scale 120 feet, or in outdoor Book of War I say it's 480 feet).

    It's really easy to be confused by this; you have to pay close attention to the particular edition you're playing. Here's a partial table I made for man-to-man miniature scales: here.

  11. Follow-up -- As a basic clue, whenever you see something like 12" in D&D, then that must be legacy miniature scale, and it symbolizes something like real-life 120 feet (varies). But if you see text like "180 feet" or 180', then it directly indicates that number of real-life feet.