Indoor Missile Ballistics

I wrote a bit about missile ballistics previously. Part of that discussion is predicated on the observations that (a) the move and range statistics given in Chainmail show signs of excellent research, and are very historically accurate, but (b) the transition in OD&D from outdoors-to-indoor via a simple yards-to-feet conversion (and no time scale conversion at all) was pretty much not thought out at all. Here's a bit more on that.

If we take the original Chainmail maximum ranges for missiles as a starting point (assuming base level of historical accuracy), in each case we can use some ballistics calculations to back-calculate the launch speed of the missile in question. Then we can use that value to calculate the indoor range of the missile, under different ceiling heights. Consider the following results:


Tools and Assumptions

• I used the "Ballistic Trajectory Calculator" by Stephen R. Schmitt to compute outdoor launch speeds, the greatest possible angle for a given ceiling height, and the resulting maximum ranges.
  
• Maximum outdoor range is automatically given by a 45-degree shot, but with a limited ceiling overhead the maximum possible launch angle (to avoid hitting the ceiling) is usually between 5 and 20 degrees or so.
• Distances have been crudely converted using a simple 1 meter = 1 yard = 3 feet assumption. Resulting ranges in inches have been rounded to the nearest multiple of 3, the same as in classic D&D.
• We presume Earth-like gravity (9.8 m/sec^2) and an initial launch height of about a normal man's shoulder (1.5m).
• The "Thrown" category includes spears, hand axes, daggers, etc. The "Crossbow" has the same range parameters as a Composite Bow.
  

Results and Analysis

Obviously, the range of the maximum possible shot indoors is dependent on the ceiling height; a higher ceiling allows for a longer potential shot. Also, the effect on different missiles is not linear; that is, the more powerful weapons suffer more than the lighter weapons. The overall effect is to "bunch up" the ranges of the weapons closer together, minimizing differences.

An interesting data point to look at is under the 10' ceiling, played with the "old school" game scale of 1"=10'. It turns out that the Shortbow has exactly the same game range as we started with; it's 15" in both Chainmail and our ballistics-accurate indoor conversion. However, Thrown weapons are not as hamstrung by the low ceiling, and in fact their in-game range has doubled to 6". Meanwhile, a weapon like the Heavy Crossbow is relatively more disadvantaged, with a resulting game range of 18" (a quarter less than its Chainmail range of 24").

Note that Thrown weapons outdoors actually have a maximum-shot height of only 8.8 meters (27 feet) -- so as soon as the indoor ceiling height reaches something above 20 feet, they can effectively achieve the maximum-possible shot range of 90 feet (30 yards/meters), the same as outdoors.

Suggestions and Options

What to do with this? Here are several different options for using this in your D&D game:

1. One option is to use the tables above directly in your game for indoor missile fire. That may be overly complicated, however, and unnecessary: ranged combat will usually be much more limited by room size or extent of lighting.
2. If you actually game at an "old school" scale of 1"=10 feet, then you can use the standard Chainmail ranges in inches and you'll be pretty close to the physically realistic results above (however, see below).
   
3. Assuming a "new school" game scale of 1"= 5 feet, you might take the classic game ranges for bows and just double them (giving max ranges like 30/36/42/48 inches); thrown weapons quadruple (to 12"). This is pretty close to the ranges shown above for a 10' ceiling, but it's still pretty complicated, and is overly generous to the more powerful weapon types.
4. We might approximate the different bows as being practically of equal range in a typical 10' high corridor or room. For example, stipulate that every type of bow has a 30" range indoors (150 ft); again, thrown weapons travel 12" (60 feet). That's probably close enough to our improved-accuracy model.
   
5. Or, you might choose to basically dodge the whole issue, saying that additional obstruction issues reduce ranges back to the Chainmail givens of 15/18/21/24 inches (again, thinking 1"=5 feet here); lighting will probably always be less than that anyway, and we thereby keep the same balance with other movement/spell/special abilities in the game. Nevertheless, I'd strongly recommend increasing the thrown weapons range to either 6" or 12", depending on your taste in the matter.
6. Whichever option you pick above, it's pretty easy to account for different ceiling heights (if you want to). Take a 10' ceiling as your base. For a 20' ceiling add +50% to the chosen ranges. For a 40' ceiling, double the listed ranges. Regardless, thrown weapons can't ever travel more than 90 feet (the maximum outdoor range, effectively achieved with a 20 foot ceiling).
   

At the moment, for simplicity I'm going with suggestion #5 above (range in inches as in classic Chainmail, except for thrown weapons which can be hurled 12" indoors, i.e., 60 feet). If anyone uses a more sophisticated option, I'd be delighted to hear how it works out.

Wandering Monster Summary

So, I actually spent, like, the last 5 blog posts or so considering issues springing out of OD&D's Underworld Wandering Monster tables (Vol-3, p. 10-11), considering these as a presentation of a "basic" D&D monster ecology, and a comprehensive presentation of all the most common hostile monsters in the game. Here's some final thoughts:

First, it's pretty freaking cool. The different levels of OD&D monsters are fairly well balanced in both overall power (Hit Dice) and nicely scaling up the perceived frequency of exotic special abilities (poison, paralysis, spells, etc.) They're mostly all recognizable to the new or casual player, leaving crazy "wahoo" new monsters for later editions (and by necessity, special hand-placement by the DM); I think that's a good thing.

Secondly, it's specialized for one particular game campaign/setting (Castle Greyhawk, with its idiosyncratic Giant Hogs, Weasels, White Apes, Thouls, etc.), and you really should customize these tables if you use them elsewhere. The tables are so short and simple that it's really super-easy to do this customization. In comparison, I think the attempt in AD&D to create more expansive tables incorporating every one of a much larger encyclopedia of possible creatures is really a failed experiment. (Other examples of AD&D's frustrating project to generalize and disconnect rules from any specific setting/referent: Disease, Outdoor Movement.)

Finally, speaking as one of the rare gamers who received a copy of the old blue Basic D&D set tabula rasa (i.e., no contact with any older gaming community, always the initial point of contact for the game in my neighborhood using the official written text only), it's something of a shame that the original 1974 edition, with all of its intimacy and call to customization, underwent an effective "cover up" by TSR in the AD&D period. Literally not knowing what it was for many years, it's now definitely my favorite and most immediate version of the game.

Missing Monsters

So here's a bit about the monsters that appear in the OD&D Wandering Monster lists, but don't actually have explicit statistics given in those rules. A rundown by category, from most common to least:

Giant Animals. We're all familiar with these. Things listed as "Giant X" where X is some normal animal type include: Rats, Hogs, Ants, Snakes, Weasels, Beetles, and Scorpions. Most of these are in monster levels 3 or 4 (although Giant Rats are level 1). All of these have some analogous entry in the AD&D Monster Manual, so post-1977 you could use that resource to fill things in (recognizing that some monsters got boosted in the OD&D --> AD&D switch; see the last post). But what would the DM do running with just OD&D itself? Some guidelines in Vol-2:

LARGE INSECTS OR ANIMALS: This category includes giant ants and prehistoric monsters. Armor Class can be anything from 8 to 2. Hit Dice should range from 2 to anywhere near 20, let us say, for a Tyrannasaurus Rex. Also included in this group are the optionally usable "Martian" animals such as Apts, Banths, Thoats, etc. If the referee is not personally familiar with the various monsters included in this category the participants of the campaign can be polled to decide all characteristics. Damage caused by hits should range between 2-4 dice (2-24 points). [OD&D Vol-2, p. 20]

A few comments here: Taken literally, the rule in the text above (min 2HD) would make for really heavyweight Giant Rats, which are of course level 1 and given only 1/2 hit die in AD&D. Note also that the damage parameters are rather terrifying -- in OD&D, 2 dice is the same as a Hill Giant, while 3-4 dice is the same as a double- or triple-size Purple Worm (i.e., Sea Monster). Personally, looking at the Wandering Monster charts, my first guess would have been to assign a number of Hit Dice according to whatever monster level is indicated -- and you'd be accurate to the AD&D Hit Dice (or one less) in each case.

Normal Animals. Oddly, there are a few animals pointedly listed without the "Giant" identifier. These are: Centipedes, Spiders (level 1 each), and Lizards (level 2). What to make of these? Obviously, in AD&D they're each listed as a Giant type with attacks like weak poison, but there's no indication of that in OD&D. They seem to be referenced in this entry from the monsters book:

INSECTS OR SMALL ANIMALS: These can be any of a huge variety of creatures such as wolves, centipedes, snakes and spiders. Any hit will kill the smaller, while larger beasts (such as wolves) will receive one Hit Die. Generally speaking they will be Armor Class 8. [OD&D Vol-2, p. 20]

So perhaps at one point the Centipedes and Spiders listed in OD&D effectively had just 1hp? Were we meant to intuit a poison attack, if anything? It's hard to tell here. (One other thing that I point out elsewhere is how ridiculously huge the 3HD Giant Lizard is in AD&D -- pretty much like every monster given a specific size in feet there -- 15' long, whereas all other monsters in OD&D from levels 1-4 are basically human-scaled.)

Thouls. So, Thouls are listed in the OD&D monster level 2 chart, but they were never given statistics in any OD&D or AD&D publication. Looking only there, I might think to give them 2HD (by level) and some abilities like Ghouls (of whom they seem cognate, and they come immediately prior to in the encounter table). Of course, Moldvay Basic D&D later gave them 3HD, paralysis, regeneration like a troll, and the appearance of a hobgoblin. Perhaps more interestingly, we have evidence that the original Greyhawk Castle notes show the monster with 4HD and similar abilities -- which would make it distressingly powerful compared to other creatures on the level 2 list. (This information from Gygax, via Gene Weigel, via T. Foster over at the Dragonsfoot boards.)

White Apes. These occur in the level 4 listing. Granted all the "John Carter from Mars" references, it's pretty obvious that these refer to the White Apes of Barsoom, who appear alongside such types as Apts, Banths, etc. (mentioned in the first quote above). These are huge, 4-armed, semi-intelligent gorillas lacking any direct statistics in D&D. I assume that AD&D's "Ape, Carnivorous" (5HD) is the replacement here, although it only has standard limbs. 3E D&D has the "Girallon" monster which is quite obviously the White Ape under different trade dress (7HD, huge, white-furred, and 4-armed; stats here and picture here).

Other Considerations. The preceding account for all of the OD&D Wandering Monsters that lack statistics in that game. Here's a few other thoughts:

Let's say you think to replace the missing monster stats with stuff from the AD&D Monster Manual. You've got to be careful for a few reasons. First, note that some animals may not have been intended as "giant", but that's all you have available in the MM. Second (and related), note that some amount of Hit Die inflation occurred between OD&D and AD&D, and that might be true for the missing monsters as they appear in the MM. Third, you've got to make some decisions about exactly which AD&D monster of several sub-types should fill the slot (my suggestions, generally looking for appropriate Hit Dice and size: Spiders-->Large Spiders, Lizards-->Giant Lizard, Giant Hogs-->Wild Boar, Giant Beetles-->Boring Beetles, Giant Snakes-->Poisonous or Constrictor Snakes?) Fourth, and again related, some of these types will skew more dangerous than others on the same list (e.g., poisonous large spiders HD1+1 at level 1, giant lizards HD3+1 at level 2). In particular, using either of AD&D's Poisonous or Constrictor Giant Snakes at level 3 is really dangerous (respectively HD 4+2 or 6+1 by special attacks each; compare to Ogres listed at level 4 without any instant-death ability) -- I recommend a 3HD Constrictor type at that level.

One final peculiarity is that, for some reason, most of these types have damage entries listed in Sup-I Greyhawk, but are still missing the more basic stats (AC, MV, HD, etc.) To see this, remember that throughout OD&D, basic monster stats were in a separate table/location from attacks and damage (those being introduced in Sup-I -- and really this whole issue is what made the Monster Manual product so highly desirable and the first publication in the AD&D line). So if you look at the new, large Sup-I attacks/damage table, although they're all strung one-after-the-other in a single unified listing, you see three identifiable sections: 1st, all the original monsters from Vol-2 (Sup-I p. 16-18); 2nd, "missing monsters" of the type we discuss here (midway down p. 18); and 3rd, all the monsters being introduced elsewhere in Sup-I (p. 18-19).

Just looking for a moment at these orphaned damage entries, we see these types -- Giant (Sumatran) Rat, Wolf, Dire Wolf, Lion, Sabre-tooth Tiger, Giant Weasel, Mastodon, Giant Spider, Giant Lizard, Giant Toad, Giant Snake, Giant Crab, Giant Beetle, Giant Scorpion, Crocodile, Tyrannosaurus Rex. Note that the spider and lizard are now explicitly "Giant". While many of these damage stats match what you see in the Monster Manual, that's not the case for any of the monsters with multiple sub-types in AD&D, so you can't use that to synchronize them (e.g., snakes, spiders, beetles). For example, the entry for the Giant Snake indicates Attacks: 1 bite/1 constriction, Damage: 1-6 bite (poison noted), and 2-8/turn of constricting; now, if I allege above that the poisonous or constrictor snakes from AD&D are particularly scary, imagine an OD&D snake of the same hit dice that's both poisonous AND constricting. Holy smoke! (Recommend bumping that to a higher monster level if you use it.)

But irrespective of these Sup-I damage listings, there are still no basic stats anywhere in OD&D for our "missing monsters". Were they originally intended to be in Sup-I Greyhawk and got edited out at some point? Interesting to think about.

Hit Dice Inflation

Did you know that, in the switch from OD&D to AD&D, all undead were given a 1-hit-die addition (excepting ghouls)?

Most other monsters were, no surprise, simply copy-and-pasted into the Monster Manual -- sometimes with minor hit-point adjustments. Other monsters that got a hit-die boost were the Draft Horse (from 2 to 3), the Ochre Jelly (5 to 6), and the Medusa (4 to 6). Rocs went from 6 to 18, but even in OD&D the 6HD figure was noted as being for a "small variety", and subject to being "doubled or even trebled". The Pegasus went from 2 to 4HD, thereby flip-flopping the old Pegasus-Hippogriff rivalry (the latter keeping its 3HD in both editions).

Oddly, the Balrog (i.e., Type VI Demon) managed to go down in Hit Dice, from 10 to 8, and here's why: Earliest printings of OD&D included the Balrog at 10 Hit Dice (exceeded only by the biggest giants, dragons, and hydras/worms in the game), later redacted for intellectual-property issues. They later re-appeared as the Type VI Demon in Sup-III Eldritch Wizardry -- here with the novel listing of 8 hit dice footnoted as being 10-sided, i.e., the same basic expectation for hit points as the earlier 10d8 (as of Sup-II). Then in the switch from OD&D to AD&D, this footnote was stripped out, leaving them with the fairly meager 8 Hit Dice that you see in the Monster Manual.

(Personally, I have to condemn this kind of overly-clever fiddliness in Sup-III as being a totally unnecessary complication, poorly thought out in its implications such as for saves and to-hit scores, a symmetry-breaking anomaly in the core mechanics of the game, and precisely the kind of weak link that causes glitches in the AD&D version of the Balrog-based demon that we see here.)

Obviously, every edition has various inflations built into different parts of the product: for an analysis of changes from AD&D to 3E D&D, see here.

Wandering Monster Numbers

After you've generated a specific wandering monster type via OD&D Vol-3 (p. 10-11), now you've got to determine the number of these monsters. Unfortunately, OD&D pretty scrupulously refuses to set any specific number for monsters found in the dungeon.

Number of Wandering Monsters Appearing: If the level beneath the surface roughly corresponds with the level of the monster then the number of monsters will be based on a single creature, modified by type (that is Orcs and the like will be in groups) and the number of adventurers in the party. A party of from 1-3 would draw the basic number of monsters, 4-6 would bring about twice as many, and so on. The referee is advised to exercise his discretion in regard to exact determinations, for the number of variables is too great to make a hard and fast rule... [Vol-3, p. 11-12]

I've posed this question before and got some good feedback. Probably the best suggestion was "if in doubt, roll 1d6". Let's expand on that just a bit.

The quote above makes a distinction for a "type... [that] will be in groups" -- I guess that would be the humanoid types in Vol-2 that potentially come in the hundreds in the wilderness? Anyway, I'm not sure the distinction makes sense. Let's say at level 1 you generate Skeletons or Spiders or Giant Rats or something. Would you really want this to be "based on a single creature", i.e., you just encounter Skeletons or Spiders or Rats one at a time? That seems quite seriously deflating.

Personally, I don't see any reason why you wouldn't also want to see these non-humanoids in a group (such as 1d6 in size), both generally for interest, and also for game-balance sake (an intent which is implied in several places in OD&D). These other level 1 creatures are not more powerful than Orcs; since they're all about equal danger level, you'd think they should appear in approximately the same group sizes. Extrapolate this further -- while 1 Ogre makes intuitive sense on level 1, once you're on level 4 I wouldn't expect to see solo Ogres by default, I'd expect to see a whole bunch of them (possibly "a street of masses of ogres", as on Greyhawk's 7th level).

Obviously, my intuition was not used in later editions, which did explicate numbers appearing in later Wandering Monster charts, and show the Gygaxian naturalistic inclination of big groups of humanoids (7-12 orcs, 6-15 goblins in DMG) and much smaller collections of other types (1-4 fire beetles, 1-4 skeletons) -- even though the latter are clearly weaker encounters overall. I think that's a mistake; but fortunately OD&D directly advises that the DM "exercise his discretion" on this point, so we have a lot more freedom here.

So let's keep it simple -- Make the "basic number" for monsters just 1d6 in all cases (excepting creatures listed in the singular). Modify this by level as follows: Multiply/divide by 2 cumulatively for each level that the dungeon exceeds/undervalues the monster level.

This is what I've started using recently, and it seems to work well in the tests that I've run. It sort of follows the 3E observation that a x2 increase in number is worth a +2 increase in challenge rating (borne out as pretty accurate when I tested it) -- although in OD&D the levels are more compressed (only 6 categories, e.g., one monster level spans two character levels of fighters/wizards), so it's looking to me like x2 numbers per +1 monster/dungeon level is most fitting. (As a side note, I'm also awarding XP on the same basis, starting at 50XP for a level 1 monster, 100XP for level 2, etc.)

The playtests that I've been doing with a slightly modified OD&D Monster Level Matrix and Wandering Monster Tables seem to work very well -- dangerous but conceivably survivable with a bit of luck for PCs of an appropriate level. In summary I currently recommend:

• Basic 1d6 of any monster per encounter (exceptions: Ochre Jelly, Hydra).
  
• Multiply or divide by 2 for each level the dungeon differs from the monster, i.e.:

1. Multiply/divide by 2.
2. Multiply/divide by 4.
3. Multiply/divide by 8.
4. Multiply/divide by 16
5. Multiply/divide by 32.

For deeper dungeon levels, roll the indicated multiple of dice and add. For lesser dungeon levels, roll one die and divide by the indicated number, rounding up on a fraction of 0.5 or more (minimum 1 monster).

Wandering Monster Tables

Today we'll look at the Wandering Monster tables ("Monster Level Tables") in OD&D Vol-3, p. 10-11. I won't recreate all of the tables here; I'll just present some summary analysis and comments.

These tables come in Monster Levels 1 to 6 (like most things in OD&D), and you'll be consulting some random one based on a roll on the Monster Level Matrix before it (see previous post). The 1st-level table has 8 monsters, levels 2-4 have 10 monsters each, and levels 5-6 have 12 monsters each. (Compare to the OD&D spell lists which also have increasing numbers of entries at the higher levels.) The specific monster you get is determined by a simple roll of the equivalent die (i.e., a uniform probability distribution and a one-to-one correspondence).

Now, analysis is somewhat complicated because many of the lower-level monsters (mostly giant varieties of normal insects and animals) are not given specific statistics in OD&D. You get some very general guidelines in Vol-2, p. 20, but basically the individual DM has to intuit appropriate stats. I'll write more about this in a later post -- but for now let's agree to fill in the missing stats from the AD&D Monster Manual and use that as an approximation.

Here's a summary of the Hit Dice at each level (after discarding a small number of outliers). Analysis follows:

1. Range: Up to 1+1. Average: 1.
2. Range: 1+1 to 2+1. Average: 2.
3. Range: 3 to 5+1. Average: 4.
4. Range: 4 to 6. Average: 5.
5. Range: 4 to 8+2. Average: 6.
6. Range: 5 to 12. Average: 9.

Monster levels are based directly on Hit Dice. It's pretty easy to see that monster levels are based simply on Hit Dice. 1 HD creatures are all in the 1st level chart. 2 HD creatures are all at 2nd level, all 3 HD creatures at the 3rd level, etc. At higher levels, you get a wider range, but the bounds are always increasing (or at least, nondecreasing). On the one hand, there's no provision for a low-HD but powerful-special-ability monster to get bumped up to a higher level (that would be a development for later editions of the game), but at the same time, OD&D special abilities are more-or-less scaled to the Hit Dice of the monster anyway.

NPC classes are also based on Hit Dice. A number of entries specify NPC class types, and their positioning is again dictated purely by OD&D-style Hit Dice (always d6-based). For example, consider the magic-users: the 2nd-level chart includes Conjurers and Theurgists (HD 2 and 2+1 in Vol-1); the 3rd-level chart includes Thaumaturgists and Magicians (HD 3 and 3+1); and so on and so forth. This is one case where the danger level of magic-users is probably underestimated by looking solely at Hit Dice. (Note also that different levels of a given class generate multiple entries in the charts, so, lots of NPC entries; I think I'd prefer if these were merged to a single entry in each table, i.e., more room for non-human types.)

Clerics are largely missing. Guess what? Whereas there are entries for almost every level of fighter or magic-user from 1-9 or so, clerics are uniquely missing from the majority of the tables. In fact, they only appear in two places: Evil Priests at level 4 (cleric level 3, HD 3), and Evil High Priests at level 6 (cleric level 8, HD 7). I'd argue that this is yet another example of the game resisting a full commitment to integrating Catholic-style clerics into the milieu, partly due to the clash in thematics that they represent.

Inclusion if and only if the monster is hostile. Look at the OD&D Monster Reference Table, which spans two pages at the beginning of Vol-2 (pages 3-4). The first page (p. 3) covers all the basically hostile-to-men, dungeon-dwelling monster types (humanoids, undead, and classical chimera-types), and everything on this page is included in the OD&D Wandering Monster charts. The second page (p. 4) covers all the benign-to-men and/or fey/enchanted-woods-types, and almost nothing on this page is included in the dungeon Wandering Monster charts (with two exceptions: Minotaurs and the Ochre Jelly). Later D&D products include entries such as for dwarves and elves in the dungeon wandering monsters, but they do not appear here for OD&D -- and I personally find this to be highly laudable. Consider how this neatly implies the "always attack by default" rule for the OD&D Reaction Table (discussed previously here).

Frequency of special abilities increase with level. While it appears that monster level determination is based largely on Hit Dice (see above), the tables also have the very satisfying quality that the prevalence of monsters with powerful special abilities increases monotonically by level. If we count up monsters with major special abilities (such as poison, paralysis, regeneration, hit only by silver or magic, spell-casting etc.) we obtain this:

1. 2/8 = 25%
2. 4/10 = 40%
3. 6/10 = 60%
4. 6/10 = 60%
5. 8/12 = 67%
6. 9/12 = 75%

(I suppose if I gave full reign to my tiny bit of number-OCD, I'd want to see that statistic at the 3rd level be 50%; perhaps by making the snakes there non-poisonous, or something. A longer rant on those snakes in particular awaits for the later post.)

Idiosycratic animal inclusions. The insect/animal types included on these tables (mostly missing stats as noted above) are not exactly what I would think to initially associate with D&D. First of all, while most are noted as "Giant" types (rats at level 1; hogs, ants, snakes, weasels, beetles, and scorpions at levels 3-4), several are not. At levels 1-2 you've got Centipedes, Spiders, and Lizards listed without that identifier. While later AD&D shows Giant versions of each of these, it's unclear exactly what's meant in OD&D; poison is not suggested for them in the LBBs, and Vol-2 suggests "any hit will kill the smaller" in its guidelines for types like these (p. 20). Secondly, the common inclusion of above-ground mammals like Weasels and Hogs (not even boars at this point) on deep-level dungeon charts really rubs me the wrong way -- noting, of course, that among the many levels of Greyhawk Castle, "The sixth was a repeating maze with dozens of wild hogs (3 dice) in inconvenient spots, naturally backed up by appropriate numbers of Wereboars." (Gygax writing in Europa Magazine #6-8, April 1975 -- thanks to Allan Grohe for documenting that here, 1st paragraph).

Mostly missing the clean-up crew. As noted above, the Ochre Jelly appears at level 3 (uniquely, but for the Hydra, listed in the singular), yet none of the other "clean-up crew" amoeba/slime types do. This is particularly odd because elsewhere it's implied that these types should be found only as wandering monsters. ("Note that Ochre Jellies, Black Puddings, Green Slime, etc., are generally distributed randomly, usually in passages, without treasure."; Vol-3 p. 7).

Outliers. I mentioned above that for Hit Dice analysis purposes, I discarded a small number of outliers, so I should detail what they are. At the 2nd level you've got Thouls, which are entirely missing from OD&D and AD&D (more in a future post). You also have Lizards at the 2nd level; if this is the same as AD&D's Giant Lizards, then they have higher Hit Dice than anything else at that level (HD 3+1), and they're also the only huge-sized creature until levels 5-6 (15' long; noting that I think the size listings introduced for AD&D are generally over-inflated, and could be cut in half). At level 4, those troublesome Evil Priests have significantly lower hit dice than anything else (3), and at a level 6 the Purple Worms have much higher dice (15), so each of these I've precluded from the Hit Dice statistics above.

Conclusions. In general, I think the OD&D wandering monster tables are highly praiseworthy in being meaty, well-themed for D&D, highly playable, and sufficiently limited in scope as to be easy to use and highly manageable and comprehensible. They present mostly mythic, recognizable-to-the-layman creatures. There are just enough monsters present to believe that they could possibly all exist in some particular megadungeon somewhere (i.e., Greyhawk). They compare favorably to later iterations such as the AD&D DMG tables which are overly large and fiddly, reduce interesting creatures like Skeletons and Zombies to near-absence in favor of a truckload of rats/beetles/shriekers, and are subject to the complaint that they don't make any sense as a presentation of a particular dungeon ecology. In the few OD&D cases where some particular entry presents a monster that is missing, duplicated, undesirable, or overly idiosyncratic, then it's a trivial operation to use the slot for something more common in your own personal dungeon or campaign (notably Thieves, for example).

I really like the simplicity of these tables for the most common basic D&D monsters, and I wouldn't think that anything more complicated is really desirable (e.g., see AD&D DMG, FF, or MM2). If monsters more rare than those on these lists require hand-placement by the DM, then I think that's a good thing, as well.

Wandering Monster Levels

This is the first in a series of posts on the math behind the presumed dungeon-monster ecology in OD&D. Specifically, we'll be looking at the various Wandering Monster tables and figures presented in OD&D Vol-3, p. 10-11. Interestingly, there's significant evidence that these tables came out of particular Greyhawk Castle play (thereby being representative of that specific setting), whereas later publications moved in a direction of greater generality.

In each edition of D&D, there have been tables for Wandering Monsters, and they're often dual-purposed for such things as random dungeon stocking, etc. Before these tables are accessed, there is something like a "Monster Level Matrix", which I'll look at here; consider the versions in Holmes, OD&D, and AD&D (in order of increasing complexity):


Now, what I've done here is not directly transcribe the tables themselves, but rather convert them to frequency statistics (i.e., showing which possibilities are most likely; OD&D rolls 1d6, Holmes 1d12, and AD&D 1d20).

Holmes has about what you would expect. In each dungeon level, the equivalent level of monster is most common; the others are sequentially less likely, or, at 2nd level, they're equally split between small numbers of 1st & 3rd-level monsters. Simple.

Now look at the Original D&D tables. They're tough, man. At 1st level, the possibilities are even between 1st & 2nd level monsters. On the 2nd dungeon level, the most likely encounter is already 3rd-level monsters! (For example: Wights, ochre jelly, giant snakes, 4th-5th level fighters, 5th-6th level magic-users.) By the 3rd dungeon level, 4th-level monsters predominate (Including: Wraiths, giant scorpions, lycanthropes, gargoyles, white apes, 6th level fighters, 7th level magic-users). Notice how many of these require magic weapons to hit, or have energy drain or poison abilities, or are just generally very tough at this level.

I think I can come out and just directly say that this OD&D table was pretty much in error and not terribly well thought out. It just gets excessively tough really quickly; there's no balanced place for 2nd-level PCs to explore, for example.

Now let's look at Gygax's follow-up with the AD&D tables (stretched out from 6 to now 10 levels of monsters). Here, the 1st-level monsters are most likely at both the 1st dungeon level, and also the 2-3rd dungeon level category. Not until the 4th dungeon level are 3rd-level monsters more common than others -- and that's still the case at the 5th dungeon level. Rather oddly, low-level monsters continue to appear at every possible level of the dungeon. Clearly the advancing deadliness has been much toned down compared to OD&D. (Still, 2nd-level monsters fail to be most common at any level. And why are dungeon levels 2-3 singularly merged? Possibly an overreaction to the 2nd level jump in OD&D?)

I think this is a case where Holmes presents a reasonable, happy medium, one that seemed to escape Gygax as he veered from too-deadly in OD&D to somewhat too-fiddly and forgiving in AD&D. My personal preference would be an OD&D-style table (based on d6 and 6 levels of monster) that had a more regulated increase in risk level.