Friday, March 10, 2023

20-Block Dungeon Stocking

 I've drawn inspiration from the article "Monsters and Treasures in the B/X Dungeon" on Spriggan's Den. The simple insight it makes is converting the dungeon stocking probabilities into their base proportions, so X-in-6 chances become a checklist-- in an 18-room dungeon, you want 3 to contain monsters with treasure, 2 to contain traps, 5 to be empty, and so on. Everything I set out in this article, which describes how I stock a dungeon in 20-room chunks, is an annotation on that idea.


A. Choose Special Monsters

A d6 encounter table is the right size. If you're putting several blocks together you may want to make different tables for different parts of the dungeon, but a d6 table is good because it allows for variety while repeating enough to give a sense of place. You should select creatures that you find interesting, not just creatures you think can serve a particular role. Putting goblins on your encounter table because you need a weak enemy is not likely to be as compelling as putting goblins on your encounter table because you read Goblin Market and got scared of goblins. One good way to find monsters is to look through your book's bestiary for creatures you like but haven't used before. (I did this for Little Snake's Man's Cave and got to use all of them together!) Another good way is to shut all books and think of intuitive, evocative freaks.

Of your six encounters, (and these will overlap):

  • 2-6 able to communicate.
  • 3-6 strategy or ability in combat besides repeatedly hitting a target. An alternate attack that makes you save vs something horrible is good. Lifting up a puny mortal by the foot is good. Throwing your coinpurse and running immediately is good.
  • 1-2 Undead, if your game has something like a standard cleric class.
  • 1-3 includes creatures you can't readily stab to death, either immune to attacks like a stone tiger or disparate like a swarm of rats or a glob of goo.
  • 1 humanoid if none of the others are, or 1 non-humanoid if all the others are.
It is permissible for creatures of the same type to fill multiple entries on the table, if they're differentiated in some way. Mixed groups of creatures are encouraged, and if at least one creature in a group has one of the traits above, it "counts" for stocking your table.

The Derro. I wanted to put this monster at the top but then people looking at the preview on Discord would have to see it and that seemed rude.
B. Choose a Scenario

Good dungeon situations are simple. They contain some fantastical element and involve some ongoing or recent event that makes the area relevant to those outside the dungeon. A remote fishery operated by a lich's dead automata and his crabfolk allies is an interesting place, but make sure they're affecting the outside world. Maybe they're selling cursed crab cakes or robbing the graves of nearby villages for workers.

Some fantasy media will be bad inspiration for a dungeon scenario because it will be saccharine and abstracted. All art forms have their gems, but there is a proliferation of ungrounded tabletop games drawing from bland video games drawing from uninspired movies drawing from misunderstandings of esoteric tabletop games drawing from commercialized short stories based on surface-level understandings of myth grounded in a fertile real-world storytelling culture. There is a reason almost every culture tells stories of betrayal, wonder, love, war, infidelity, dead people speaking, house spirits, and miracle workers. Try to tap into ideas that still have some juice in them. They don't need to be original but they should be exciting and emotionally grounded. If you're working in a setting inspired by Grimm fairy tales, you don't need to settle for reading TVTropes synopses or watching Neverafter-- Grimm tales are very accessible! Such is true for the many classic and/or children's and/or folk stories that are liable to have a lot of creative juice worth squeezing.

This is the time to decide some general features of the dungeon space. Unless otherwise noted, what are the doors, walls, and ceiling like? What do the doors look like? What smells prevail? List your assumptions.

from the Ouroboros of the Orb Oracle
C. Stock the Dungeon

Spriggan's Den gives us the proportions for an 18-room dungeon thus:
  • 3x monster with treasure
  • 3x monster
  • 1x trap with treasure
  • 2x trap
  • 3x special
  • 1x hidden treasure
  • 5x empty
Our dungeon is going to be 20 areas, or built in 20-area blocks, so you decide which of these categories you're going to have extra of, based on the kind of scenario you've chosen. My megadungeon Coyce includes a slight bias towards traps (having 3x) and special areas (having 4x). Often the character of the dungeon will have crystalized in your head by this step, but if not my standard advice would be to add +1 monster with treasure and +1 empty area. Later when we decide how to allocate treasure this means the spoils are more spread out, not necessarily that there is more of it.

The Basic Rules stocking procedure doesn't list everything that you'll want in a dungeon. 
I recommend including the following:
  • stuck door
  • locked door (possibly with a key to be found elsewhere)
  • two or more secret doors
  • magic scroll (in games where magic-users learn spells this way)
  • construction trick (like a sliding wall or imperceptible slope)
  • text in uncommon language
  • two or more descents/ascents of one or more levels
  • poison (deployed via trap or enemy)
  • disease vector
  • effect that changes primary attributes
  • effect that can change PCs in a unique, indefinite way
When stocking a dungeon space, I tend to refer to each "room" as an "area", as that helps to remind me that these are points of interest which may not be an enclosed cell. A large room might have two areas in it if there is some other natural border, and you should feel free to designate areas in the outdoors around the dungeon as relevant areas. Every area within the dungeon space should be keyed somehow, even if it's just as an empty room. This includes hallways and stairways that aren't contained in another area.

Since we haven't drawn the map yet, don't give exact dimensions. Each area should be defined by its contents and sensory details. If something is hidden, it should be hidden by something else a player might decide to investigate. Keep an eye to "enrichment"-- simple obstacles and things to interact with keep people engaged.

Areas with keyed monsters can draw from the random encounter table. If there are intelligent creatures here, where is their camp or the center of their community? If there are animals here, where do they den? Keyed monster areas are good places to put powerful creatures, since players can plan around the most dangerous creatures in an area better when they have a good idea of where they are. Keyed monster areas are also a good space for "choreographed" fighting spaces. Perhaps the monsters have built a fortification or trap, or perhaps they're at ease in an area and can't fight with their usual armaments or preparations. These can also be good opportunities to encounter dungeon denizens at peace, perhaps an old dependent or camp followers who aren't interested in fighting.

Areas with keyed treasure should take measures to ensure the treasure feels weighty. If there are coins, they should be heaping. I've seen dungeons where some big object is gilded and PCs are almost invited to scrape the gold leaf off as a treasure, but this is a big missed opportunity. By all means, make treasures difficult and time-consuming to acquire, but don't make it tawdry. Better to have a golden statue that is tricky to extract, or a locked chest that certainly contains coins. Treasure can also take the form of tools and valuable objects, but they should still feel special. It can be possible to include too many magic items, but it's no fun to have too few. I recommend one or two major objects, a spell scroll or spellbook, and a generous helping of very minor or consumable magic items. Against detractors, objects that give flat numerical bonuses, like the +1 sword, can be very cool if invented with lurid and savory description. This is more true in games like basic D&D, where small bonuses are rare and potent. In Pathfinder games it may be harder. Beware magic items that negate problems, but love magic items that help to solve problems in new ways.
The overall value of treasure in a 20-block section, not counting magic items, should be commensurate with the danger of the space. In basic D&D, you can pick a presumed character level, multiply the amount of XP that is needed to achieve that level from the previous for a fighter, multiply it by four, and add a little on top. So for a "first-level" dungeon block, that's 2000 x 4 = 8000 + a bit extra for 10,000 gold coins. To achieve the "heaping treasure" effect, it makes sense to put the biggest hoards in dangerous or remote areas. Pair smaller hoards with cool magic items or keep them in small forms, and give them some detail. A ring or emerald worth 10 gold found in an old tin among 100 old silver coins is much cooler than finding 20 gold coins on the floor. Wrenching a 6-gp gold tooth out of the mouth of the sorcerer who just shot at you with his Wand of Cut In Half is just icing on the cake of getting your hands on the wand. Remember, life is short and XP progression is quadratic-- be generous with gold in gold-for-XP systems.

Areas with keyed traps want other details to hide them. Players should have the chance to preempt danger and interact with a trapped area carefully, but it's too easy if the trap is the only object in the room. Lay a carpet in the middle of an empty cell and a careful PC will tug it away. Put a cabinet full of decorative spoons on the other side and they may step onto the carpet and fall down a chute. It's important to have a good idea of what triggers a trap and how PCs can interact with its workings, but it's also important to have some fun with it. Grandiose traps are fun, and whenever you include a simple dart trap or pitfall it's worth asking yourself if you can give it some pizazz, even if it's just a magic mouth that yells "You fucked up!" when the swinging blades shoot out.

Keyed special areas are a very good opportunity for the "effect that can change PCs in a unique, indefinite way" mentioned above. These could be delivered unwittingly, as in a trap or cursed object, or offered as an option, either by an NPC or some environmental storytelling. Other good uses of special areas include those that give more information, such as a market or library. I like to include a strange merchant in many of my dungeons. If you can, think of some really crazy ideas for what can be in your dungeon, then see if you can bear to put any in. Any good puzzles you have are acceptable. A lot of standard advice for special rooms include things which can be considered traps or else features that are worth including but sort of feel like wasted uses of the keyed area. By all means include graffiti, secret teleport traps, murals, upside-down rooms, saunas, and landmarks. Include them as features of other areas.

Keyed empty areas are never truly empty. They're just empty of monsters, traps, treasures, and special things. It's good if these contain some obstacle, or something to interact with. A well-stocked kitchen would be a good empty room. PCs might spend a lot of time there, and might use a bag of salt they find to slay an evil goo later that day. Empty rooms might convey information in the form of graffiti or spoor, or by overlooking other dungeon areas. If you want to include an area to characterize the dungeon but you don't have a good idea for it, it could be a good empty room. Like if you wanted to have a spooky torture chamber but can't think of anything more interesting to put in it than the standard black-hooded-guy whipping a dwarf, may as well just include it as an empty, transitional space.

An important tip for any kind of area-- don't forget that these dungeon tropes reference real and literary things. Think about how exciting it is to find a hidden area in your favorite Zelda game, or to see characters discover a secret passage in a film. This method involves checking off a lot of boxes, but the content of your dungeon space shouldn't feel rote. Outside of an adventure game context, deathtraps are cool! Glittering piles of gold are cool! A goblin is scary! Never lose sight of that. Incorporate it into the game.
It doesn't need to look good. Its beauty is its function.
D. Draw the Map

First, draw three or more intersecting circles lightly on a piece of graph paper. This is the general shape the routes between the areas of your dungeon will follow, which is a simple way to ensure they will have sufficient loops and jacquaysion. If you deviate from this outline, that's fine.

Then, start blocking out the twenty areas in whatever way you choose, keeping in mind the areas you wanted to serve as dungeon entrances, the ones you wanted to be further back, etc. Try to keep room shapes simple for ease of description later. I like to stick to rectangles and circles unless there's some reason to deviate. One cool trick to watch out for is to see if you can create symmetries or patterns. Players might be able to pick up on these to help navigate, possibly even finding a hidden area. Use secret doors and hidden passages to conceal small and interesting areas or to provide quick routes throughout the dungeon, but don't fully cut off a large section of the dungeon behind one. 

For naturally-formed dungeon spaces like cave systems, it's perfectly fine to draw each chamber with a simpler perimeter than it might have in real life. Make sure to pinch the connections between natural chambers, perhaps to doorway size, to avoid the issue of PCs entering one area and getting visual descriptions of too many things at once.

You may have to reorder the numbering for your keyed areas, but with only 20 that shouldn't be too hard. For your own ease, try to number the areas so a party proceeding through a loop will cause you the minimum amount of page flipping or scrolling. If one area is a dead-end or branch off a main loop, it's usually better to number that branch, then the rest of the loop. Whatever happens, it will be impossible to avoid some jumps because you designed a dungeon with loops and double-backs, and that's fine. Other than numbers, consider if there are any notes that really belong on the map. I might put a little x in a square if the exact spot where a trap is matters, or some other symbol to help orient myself when interpreting an area's description.

E. Finishing Touches

A 20-area dungeon is a perfectly good size to me but this method can also string multiple blocks of dungeon together. The megadungeon Coyce is made up of multiple levels of two or three blocks each, every new level possessing its own encounter table. If you do string blocks together, it can be fun to establish extra minor motifs when stocking the dungeon. For instance, at least one empty area in each block of Coyce has signage of some kind, at least one trap area and one empty area has a lever of some kind. Little touches like these can help the whole dungeon hang together.

Note that if made as I suggest, even a single block dungeon will have descents and ascents to different levels. This engages the third dimension and lets you do fun thinks like creating secret doors in a ceiling chute or pitfalls that lead to monster-infested quarters, but if inconvenient to your mapping preferences they can be ignored.

If you haven't already, come up with a cool name for your dungeon area and think about what PCs might learn about it. Fun rumors hint at the contents of the dungeon or will lead the players to make choices they wouldn't otherwise make. A rumor is bad if it has no effect and isn't even funny.

You are ready for A D V E N T U R E !


  1. Excellent work, and incredibly useful.

  2. Cool, thanks for sharing your process! I might try it at some point!
    The recommended elements checklist is also a nice addition...

  3. This is one of those posts I print off and add to my personal DM binder. Thank you for writing this!