In Memoriam
The Deep Halls vs Quasqueton

One Deadly Dungeon

“…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 adventurers or in the third level of the dungeon if the monsters appearing are first level.” (Holmes, 10)

Other than a hint in the wandering monster table, with more and more powerful monsters found on levels two and three, this allusion to the increasing danger in deeper levels is as close as Holmes1 gets to a standard conceit of old-school dungeons: the strength of the average monster encounter on a given dungeon level matches that of a player party of the same experience level.

That accepted, a dungeon’s deadliness might be expressed as a ratio of the number of experience points in stocked monsters and treasures a given level contains versus the amount necessary for an adventuring party to gain an experience level.

A party of 1st-level characters, for example, exploring the first level of the dungeon, should earn enough experience to gain a level before descending to the second level. For, while the adventurers still have a fighting chance, the dangers below are more likely to overwhelm them.

Scratched with an iron spike on the inside of a neophyte adventurer’s shield is the maxim, “Level up before level down.”

Closed Dungeon

I assume here a “closed” dungeon. That is, one which must be explored without delving elsewhere. Whether due to time constraint or DM fiat, the only experience to be gained is in this dungeon.

An even 1:1 ratio—experience stocked to that necessary—may not be enough to approach a minimum level of survivability. We should consider that some monsters prove too tough and some treasures go undiscovered. Further, attrition extracts earned experience from the pool.

I am not one to scrutinize the numbers. But the dungeon’s limited size prompts me to further examination. I conclude below that any foray into The Deep Halls of Amon-Gorloth is doomed to failure. This is how I figure.

Reading Map

This is another longish bit. The math is no more complicated than simple probabilities and basic algebra,2 but following each step requires tenacity on the part of the author as well as the reader. I try to move quickly through the calculations and, at the same time, remain coherent.

If you are able to follow the text—and do, then we are exploring The Deep Halls together. Suggested equipment: lantern and ten-foot pole…

Encounter Areas per Level

As an initial measure to ensure some modicum of survivability, I previously merged The Deep Halls’ seven levels into three, thereby increasing the number of encounter areas per level. Counting the areas by color, we get the following numbers, sub-totaled by level.

Level Color Areas
1st UP Red 4
1A Tan 15
1B Light green 32
Sub-total Level 1:   51
2A Dark green 44
2B Blue-green 48
Sub-total Level 2:   92
3A Blue 16
3B Purple 20
Sub-total Level 3:   36

Adventures per Character Level

“As a guideline, it should take a group of players from 6 to 12 adventures before any of their characters are able to gain sufficient experience to attain second level.” (Holmes, 22)

In my experience with both Holmes Basic and B/X, a low-level party, having not unusual luck, can explore about five rooms, before running low on spells and hit points. If by “adventures” the editor intends forays into and out of the dungeon, ten of these would clear the 51 encounter areas on Level 1.

Note that, for the present purpose, we consider only The Deep Halls’ first level. The calculated ratio is specific to that level. It is not applicable to the dungeon’s other levels or to any other dungeon. Though the calculations to derive the ratio could apply.

Experience Necessary to Gain 2nd Level

“The number of wandering monsters appearing should be roughly equal to the strength of the party encountering them. 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.” (Holmes, 10)

The goal is determine how many experience points to stock on Level 1 so a 1st-level player party might advance one level of experience before going down to the next.

Party Size

Cross-referencing Holmes’s example for balancing encounters with the Monster & Treasure Assortment Set One, we see, on the First Level table, entries for both monsters: “Orcs (2-5)” and “Giant Rats (3-12).”

Averaging the dice rolls for the ranges and dropping halves, a party of three might encounter three 1-HD orcs or seven ½-HD giant rats—a “roughly equal” match for a party of three 1-HD characters.

On M&T’s second level, the party of three, now 6-HD, encounters 3-12 orcs (average 7) or 5-20 giant rats (12). On the third level: 4-24 orcs (14) and 5-30 giant rats (17) versus the party’s 9 HD. Tenuous, but the match holds.

Further examination of the monster tables (not shown) reveals similar correspondence. We conclude that, though the M&T instructions do not say, three is the target number of party members for listed encounters.

Therefore, we use a party of three adventurers to determine a baseline. We can adjust for larger and smaller parties later.

Hereafter, I show the math immediately following the text that refers to it.

Averaging the XP necessary for each class, as a whole the party must earn 2,171 XP per member. (Note that only 4,000 XP are necessary for an elf to advance to 2nd level in the fighting man class.)

2,000 + 2,500 + 1,500 + 1,200 + 2,000 + 2,000 + 4,000 ÷ 7 = 2,171 XP

For our party of three, Level 1 should be stocked with 6,513 XP to arrive at a ratio of 1:1, stocked-to-necessary XP.

2,171 × 3 = 6,513 XP

Magic-users and elves lag—as usual.

Noncontiguous Levels

We needn’t venture far into The Halls before we have an indication of their depths. Level 1 is not contiguous (nor is any level). A 1st-level party is obliged to descend into dark green sections (level 2A) early in the exploration. We keep it in mind for later consideration. By this though, we are warned: The Deep Halls is one deadly dungeon.

Mean Experience per Encounter

Here we calculate the average XP to be gained per encounter from monsters and from treasures. Considering only Level 1, we round to 50 encounter areas for simplicity.

On the Flying Dungeon Stocking Table, monsters entries should be read as one roll on the M&T monsters table. In addition, let’s assume the “double” treasures (first two entries) are accompanied by double monsters—two rolls on the table. Likewise, single and double treasures on the Flying Table are one and two rolls for treasures.

XP from Monsters

Here, where we calculate the average value for XP from monsters, it is for a roll on the M&T tables, not for a single monster. We see on the Flying Table that monsters inhabit 33% of rooms (17), plus 10% of rooms are double monsters (add 5). So, Level 1 might contain 22 monsters.

The mean XP value of a roll on M&T’s First Level monsters table is 50. Don’t ask me how I know this.

Therefore, our party should receive 1,100 XP from monsters for their efforts.

(17 + 5 encounters areas) × 50 XP per monster roll = 1,100 XP

Wandering Monsters

It’s difficult to estimate how quickly a party explores a dungeon. By the Bluebook, we roll for wandering monsters every third turn. Considering an armored adventurer’s 120-foot move rate (Holmes, 9) and the room density on The Deep Halls map, a clever party (see below) might explore one room every three turns. A rough estimate, but it serves.

Therefore, during the party’s exploration, the DM rolls 51 times for wandering monsters, which appear 8.5 times. At 50 per encounter, that gives us 425 XP from the wandering type, which we add to 1,100 for those static, to arrive at a total value of 1,525 XP from monsters.

51 ÷ 6 = 8.5 × 50 = 425
425 + 1,100 = 1,525

A Clever Party

In calculating the ratio, I use, as a baseline, the notion of a “clever party.” An oft-touted characteristic of an old-school game is that player ability is as or more important than character statistics. New players are taught by those more experienced (whether DM or adventuring companion), and so, they learn to navigate the dungeon and overcome its challenges.

As a group, the players test their ability against the dungeon. More clever players may be more successful, thereby advancing somewhat faster in experience levels, while those less clever must learn or ultimately fail.3

Later, I expand on the notion, adding the concept of player ability in three tiers: less clever, clever, and clever indeed.

By a “clever party,” I mean one which counts among its members at least one experienced player of at least average cleverness.

XP from Treasures

From the Flying Table again, we calculate how many encounter areas are likely to have treasure and how much. Where treasures are found with no monster, I extrapolate half the amount of a roll.

Percent of 50 No. of Areas Amount of Treasure
10% 5 Double treasures
16% 8 Single treasure
5% 2.5 Treasure (half treasure)

I don’t find in Holmes any notion of rolling dice, when searching, to discover hidden treasure. He gives no explicit rule. In the sample dungeon, treasure is hidden. If characters take the time to search the hiding place (a layer of refuse, Room G, 43) or perform a certain action (cut open a defeated spider, Room J, 44) they discover the treasure automatically.

The total gold-piece value of treasures, ignoring magic item entries, from M&T’s Level One treasure table is 14,326. Don’t ask me how I know this, either. This makes the average value for a treasure roll on the 100-entry table equal to 143 gold, 2 silver, and 3 copper pieces. Please do let me know if your count differs.

Now, we can calculate how much treasure exists, according to the probabilities of the Flying Table, on The Deep Halls Level 1. I add parentheses around each treasure magnitude—double, single, half—for readability.

Where t equals one roll on the treasure table or 143 g.p.,
(5 areas × 2t) + (8 areas × t) + (2.5 areas × ½t) = 19.25t = 2,752 g.p. and change

A Party of Three Searching for Treasures in The Deep Halls of Amon-Gorloth - Map by Dyson Logos
A Party of Three, Searching for Treasures, Finds Few in The Deep Halls of Amon-Gorloth. Map by Dyson Logos.

The Cause for Concern

Adding XP from monsters and treasures, we get 4,277.

1,525 + 2,752 = 4,277 XP

Therefore, the ratio of stocked XP to that necessary is 4,277:6,513 or 66:100—not near 1:1.

Our party of three, if clever indeed, might find all the treasure on Level 1, but still earn only 4,277 XP.

4,277 XP ÷ 3 characters = 1,425 XP per character

Although a thief advances, fighting men lack one-quarter of the XP for 2nd level. Furthermore, we have yet to account for too-tough monsters, undiscovered treasure, and attrition.

So, we see that any expedition to The Deep Halls of Amon-Gorloth is doomed to failure.




We don’t heed the warning, of course. We’re adventurers after all.

I proposed earlier a fun solution to the problem: “to throw treasure at it.” Next, we’ll see how much treasure we need to stuff into The Deep Halls to make it survivable.4

The lantern is dim. Let’s take a break while I refill it.


1 Zach Howard of the Zenopus Archives compares “The Holmes Manuscript” to the published 1977 edition of Basic D&D. From Zach’s analysis, it’s clear that some text of the published version differs from that intended by Eric Holmes. The section on balancing encounters is an example. In this and following articles, unless stated otherwise, when I refer to “Holmes” I mean the edition, not the editor himself.

2 The math isn’t complicated, but there is plenty of room for error. If you notice a miscalculation, please let me know.

3 The cost of failure in the D&D game is to roll-up new characters and, bolstered by the experience, descend again into the murky depths to face anew the challenges therein lurking. We only fail when we give up.

4 Another solution, of course, is to award more than 1 XP per gold piece. Though the practice is not unheard of these days, the first I learned of it was during the early part of the current era, called the Old-School Renaissance, in the 2000s. Whether multiplying treasure or experience for it, read on, for much the same considerations apply. Grognards belch at both.


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