Wandering Monsters in Holmes Basic D&D

Today we're looking at the first-ever D&D Basic set, edited by Eric Holmes (1977). This is the first set of D&D rules I ever had my hands on as a wee lad, and it's entirely how I learned the game at the outset.

In particular, let's look at the rules for Wandering Monsters, because it presents an interesting step in the design of classic D&D encounters. This is because it's one of the few places in this Basic set where a major overhaul was made between the draft and the published set; Holmes even publicly expressed his surprise at the switch at one point. We're now fairly confident that it was Gary Gygax himself who made an editorial pass of Holmes' draft, making various insertions and edits -- mostly to align with his developing AD&D game -- and this may have been the biggest change. Recommend that you read this article at Zenopus Archives for the full story.

In Holmes' original draft, he basically reiterates the rules seen in the OD&D Little Brown Books, Vol-3 (which was his charge for the project in the first place; organization & editing of OD&D). He states that wandering monster numbers will be about one-third of PCs present, in exactly the same terms we saw in OD&D Vol-3. The tables present are the same format as in OD&D, with the monster listings basically the same as in Supplement-I, Greyhawk.

But Gygax comes in and rips out all of that and replaces it with completely different rules. The rules now read (p. 10):

First level adventurers encountering monsters typically found on the first level of a dungeon should be faced with roughly equal numbers, i.e. a party of three would encounter 2-6 orcs, 3-12 giant rats, etc. However, if the party were second level, or the first level monsters were encountered on the second level of the dungeon, the number of wandering monsters encountered should be doubled. In a like manner, the number of monsters should be tripled for third level adventures or in the third level of the dungeon if the monsters appearing are first level.

So the new rule that wandering monsters should "roughly equal numbers" of PCs seems to at least triple the danger level as seen in OD&D. Worse than that, the examples given for a party of three PCs, e.g., 2-6 orcs, seems more like outnumbering the PCs than actual equity. It seems very much more dangerous than Holmes (or myself) would pick up from reading OD&D.

While these rules still don't anywhere state an "expected standard party size", maybe the suggestion here of "a party of three" is the closest that we'll get. Gygax inserts a new custom matrix of wandering monster tables, including for the first time specific number-appearing ranges, generally in line with the examples in the text above (e.g., 2-5 orcs on the first level), which further bolsters the theory that a party of 3 PCs was that expectation (as weird as that sounds, and counter to Gygax's claim that he had upwards of 20 people at his house playing every night for his first six months of gaming).

Let's analyze the danger level of those tables using my EHD/Equivalent Hit Dice analysis (in the last column, "Prod" means the product of Average number and EHD per monster):

The average (mean and median) encounter level here is about 4 EHD; a level that seems fairly balanced (in the sense of a 50/50 chance of either side being victorious) for a party of 3 or maybe 4 PCs. In this case, since few of the 1st-level monsters have exotic special abilities, the analysis is pretty much the same as just looking at HD values (which Gygax was almost assuredly doing).

I would observe that he probably undervalued the danger from kobolds, giant rats, and the like; they have half a HD, so he basically doubles their numbers. But in my simulations they have about two-thirds the power of a one hit-die creature. (It's a common error for game designers to downplay the danger from swarms of small, cheap opponents; e.g., enemies like these have a higher action-per-HD ratio.)

Doing a similar calculation for the other levels appearing in the Holmes chart, we get:
  • 1st Level: Average 4 EHD
  • 2nd Level: Average 8 EHD
  • 3rd Level: Average 10 EHD

So it does look (as per the text) like the danger level pretty much tracks linearly with the dungeon level (roughly dungeon level × 4 EHD in each case).

But what does this all say for set monster encounters in their lairs (not wandering)? The Holmes rules don't have standard numbers appearing in their monster listings -- unlike almost any other ruleset (OD&D, AD&D, B/X, etc.). If the wandering encounters are each a 50/50 fight to the death with the PCs, are the set encounters supposed to be the same, or even more perilous than that?

Note that this model of numbers-appearing we see here is very similar to what was in Gygax's Monster & Treasure Assortment released in the same year (1977). More on that another time.


  1. I guess you meant "3rd Level: Average 12 EHD", right?

    1. No, the book 3rd level table in fact has a mean & median of 10 EHD (work not shown above). Of course I'd be happier if it was perfectly consistent with an average of 12 EHD.

  2. Replies
    1. Ah, thanks for that, I'll correct it above. The complicated copyright line on the inside cover routinely confuses me.