Friday 7 July 2023

Dark Corridors

 Choice Theory 

So you come to a split in a dungeon, or you come to a room set with three portals, each seems to lead in a different direction but they seem identical. 

Depending on party and DM, game style and preference, you either just pick one, or have a little conference with the team, maybe looking at the map, or start asking weird questions like “what do the corridors smell like?” 

Whether this is a good or bad thing depends very much on the style of game and whether the needs and intuitions of the players and DM match. 

I intuit that the ‘actual’ Old School old school process had a lot more time for no-context choices, partly due to the prevalence of player-mapping, (easier to do in-person in a 70’s game session and which would be part of their problem-solving procedure), partly due to what I would expect to be longer more digressive gaming sessions and partly due to a somewhat harder more ‘masculine’ quality where its expected that some decisions will be tricky, oblique or apparently pointless, either due to pseudo-naturalism or a Gygaxian riddlemaster element. 

I intuit that a more ‘neo’ OSR scene would have shorter sessions, more likely to be online so player mapping harder, more likely to want events and drama condensed and with less tolerance for ‘dead’ time, unguided choice and apparently contextless decisions. 

Yet, in either situation, a choice must be made, and if the choice is to be informed at all then how shall it be so? There are greater context elements which can be brought into the question; general dungeon intel, the use of mapping, informers, magic and guides.

But what can be learned from the empty corridor itself? 

And as a corollary to that decision, what information can be imbued into  that apparently-empty corridor by the designer or DM? 

I will break our discussion into elements. In lived experience all of these will interrelate but I will try to cover those interrelations within each subject; 

·        AIR

·        SMELL


·        LIFE

·        SOUND

·        STONE


Once I started to think about it I decided that a key dominating and synthesising element is AIRFLOW

so I will begin with that and discuss why.

Ernst Fuchs



Based on my research for VotE, Caves and cave systems can differ hugely in temperature and airflow. 

This depends on whether the system massively intra-connected or isolated, if there is running water in the cave and the general temperature gradient around the cave. 

An isolated cave system with no big interconnections and no water flow within will often be a bit warm. An underground space with static air will often maintain a steady, not-quite-cold temperature. Mines, being closed systems and full of people and movement, are often hot. 

Conversely, a huge cave system with many exits will often have very strong airflows. Caves 'breathe', and any slight differences in temperature and pressure between its varied entries can create winds which can be focused and channelled by narrow passages in the system itself. 

Most caves are shaped by water and many have streams moving through them, this creates airflow

and often cools the cave. 


Dungeons vs Caves 

Dungeons are more likely to be smaller and contained and much more likely to be made of different materials with closed doors and other connectors and divisions within, but airflow can still tell the prospective dungeoneer a lot. 

Dungeons, specifically; the classic tomb buried under temperate soil, might not actually be cold. A tomb complex separate from any other dungeon, well if it’s a rainy area it might be damp, but not necessarily, it might be slightly warm, or at least no colder than the outside. 

[Question; have you actually been in an actual tomb complex? What was the temperature and airflow like?] 

An experienced dungeoneer, or the average Dwarf, should be able to make some decent guesses about the nature of a dungeon just by carefully feeling the airflow. If a system is 'breathing' with air flowing in or out after dawn or dusk; that suggests a system of considerable size. If the air flowing in or out is warmer or colder than the outside air that might indicate the presence of moving water within, or of something else that is cooling or warming the air within, (like, for instance, the presence of life, like Goblins or an Owlbear). 

Airflow is such a dominant factor because it effects the transmission of SMELL, SOUND and TEMPERATURE, all of which are strongly bound within the greater medium of Air. Conversely the absence of airflow is itself a strong negative signal which might not explicitly tell you much but does suggest that either this dungeon, or system, whatever it is, is either small and closed, or has doors and closing elements.



Smell is life! 

The key aspect of scent is that in almost every case it is indicative of the processes of life. A dungeon with intelligent things living in it for any period of time is going to STINK. 

The Food Sequence 

Acquisition, Storage, Preparation, Consumption and Disposal. 

Acquisition; alpha predators like monsters who drag prey back to the dungeon as a lair will leave the stink of blood wherever they are and repeated blood trails will lead to any feeding spot, as well as blood smears and fur snatched from carried prey. 

Anything bringing living or recently dead food back to the Dungeon from outside stands a good chance of leaving marks of some kind, especially since they will be tracing the same route each time to preparation or storage spaces. 

A lot of food smells or has a distinctive scent, and in a still-air environment that scent might remain in place for a long time. 

Storage; if left unattended, the rotting bodies of victims or prey will absolutely stink to high heaven. Even for unaltered human basic smell powers it should be pretty simple to find your way through a still-air environment to a rotting body. 

Poorly-stored non-meat foods can still rot, and will summon their own micro-environment of insects and small mammals, all of which can be sensed or traced. If there are mouse droppings, that’s a sign of something. 

Well-stored or dry foods are more complex, I imagine these as leaving little scent and few biomarkers. It might be that the presence of a particular dry and contained space might leave tangential markers but I am not sure. 

Preparation; if something is intelligent and eats cooked food, and/or just needs warmth or light, then there will be fire. If there is fire there must be smoke. If there is smoke it has to go somewhere. So either there is a chimney leading up out of this dungeon or the smoke is moving through the corridors which will leave traces stains, and scent. 

Consumption; large predatory animals will definitely leave bits and pieces here and there. Smaller more civilised beings might still leave scent, the wall-sweat of their respiration, residual warmth, stains, fragments and the small biomarkers that go along with them. 

Disposal; Poo. All of this stuff has to go somewhere and unless there are convenient rivers or pits then it is going to leave strong scent markers and all the small insects which emerge from feasting on the poo. And spiders, which feast on the flies, the webs of which will remain in place for a long time in a low airflow environment. 

tldr; any closed system which has living respiring and eating residents is going to stink. If there is airflow, then its strength and direction will effect where those smells go and how strong they are. Tracing those smells might be very useful for a dungeoneer. This is one thing that encourages me in the idea of bringing a bloodhound of some kind to the dungeon 



Warmth is co-dependent on airflow and the presence of life within a dungeon so many of the basic concepts have already been considered in those two sections. 

[Question; how much of a temperature differential can an average, or sensitive human being detect if they are paying attention? Could they intuit the presence of a living being occupying a room behind a door? Could they tell micro difference in temperature in the air between two identical corridors?] 

What about cold? Would any particular natural phenomena cause a dungeon to chill unexpectedly? The first thing that comes to mind is the presence of para-normal phenomena like Magic and the Undead. Both are often associated with rapid temperature drops. 

Conversely, super-beasts like dragons or elemental creatures might raise underground temperatures more than you would expect. 




SWEATY WALLS! Why are the walls of the dungeon dripping, dank, with the nitre, so beloved of Lovecraft? It may be water flow from outside but more likely the combination of water and warmth coves from living things in the dungeon. A system of closed stone with living things within it will naturally sweat, and drip, over time. 

What about the sweaty walls of a sleeping dragons cave? Why wasn’t the gold surrounding Smaug absolutely dripping with condensation? Maybe it was and that is what caused Bilbo to slip and slide around. Wet Hobbit action. 

[Question; have any of you actually been in an actual Dungeon, under an actual castle, working or not? Are they actually the cold, dark, dripping places of fiction?] 

I mean clearly they are made not to be comfortable, but surely actual temperature would depend on how much airflow there is, or the temperature of the living rock, if its carved into that. 

Would a dungeon under a living castle with locked doors and no windows, truly underground

actually be cold? Or might it be temperate? It would be damp I think due to the respiration of everyone above in the castle and their condensed breath dripping down.


Lichen, Moss, Mushrooms, Insects 

I feel like Gary must have at least conceived of a grand table of microflora and microfauna that might grow in a dungeon and have the required and likely temperature ranges, water needs, food sources, and, in the case of insects and small mammals, roaming distances. 

I am taking being a dungeon detective a bit too far here, into Forensic territory, BUT - IF you did actually know a lot about these micro-environments you could in theory tell quite a lot about a dungeon just from observing them as you went through. 

This should go for Rot as well, a microorganism which leaves sensory traces. A rot wizard could tell quite a lot about living systems. There is probably an opening somewhere for someone to produce a matrix of easy-to-use and 'read' pseudo-realistic dungeon microfauna, not for use as enemies or 'colour' but as a kind of spread of information that can be observed to tell what kind of things have gone on in a dungeon. 

This, because of its complexity, I think I know least about. I know a bit about cave fauna, but the secret of that is that, beyond a certain depth, there really isn’t much of it. Without light you get near-nothing and so far as I know, mushrooms will not actually grow on the cold limestone of a cave wall. 

[Question; does anyone out there know if lichen will grow in dark conditions? Or any such moss? Any fungal experts who can say which foods and temperature ranges are needed for fungal growth?]


Unknown Artist



How does sound carry underground anyway? Irregularly I would think. It must depend a huge amount on the substance and layout of the place. Some shapes and materials I know just EAT sound, but in others, small sounds can travel a very long way. 

[Question; does anyone know about what kinds of stone, material or corridor shape interact how with various sounds? Do the stone walls and floors of a classic dungeon echo with footsteps of mocking laughter as Gothic novels claim? Can anyone confirm?] 

The most important matter must be FREQUENCEY. Specifically, is there anything in this dungeon that produces a low-bass sound, like stone scraping, or something huge moving or rolling? Those low frequency sounds travel a lot, through materials more than air. How many times on a quiet day have you realised a big truck is moving several street away, or a washing machine or other large device is working several rooms, or an entire property away? 

A sleeping dragon, for instance, will produce not only sweaty gold but probably a very deep, but soft, sound that might transmit strongly through stone. 

Doors opening and closing; if these are on hinges there is a good chance they will be badly maintained and so screech. They may also thud and slam. Stone doors may produce the deep frequency sounds that transmit so easily. 

Living things; the biomarkers we talked about in the ‘Smell’ section. Is there scampering? The buzzing of flies or mosquitoes? The crawling of insects? 

Consistent background sounds - Water should produce some kind of distant continual sound

likewise, wind changing outside the dungeon, rain, storms, these should produce some sort of effect, unless there are many portals between here and there. 

Is this place indeed as 'Silent as the Tomb'? If so that itself might be quite unusual.  In a state of such absolute silence it might be that very super-quiet noises which are usually indiscernible could become more prominent, like the crawling of a bug for instance, or the shifting of dust. 

At what distance and in what circumstances can we expect living inhabitants to produce discernible sound? 


by Art of Raman


Or whatever material the dungeon is made of. 

You would probably need to know a lot about bricks, or slate flags, for micro differences in them to be useful in any way, but.... aren't dungeoneers (and Dwarves) exactly the type to pick up just such knowledge? 

What could we reasonably expect a skilled observer to pick up from various arrangements of building stone in separating corridors? Could they guess which corridor was built first? If one is a later addition to the other that should be obvious should it not? as well as the various skill and the resources available to the builders. 

A culture in decay producing less perfect masonry, or cutting into a stone-lined corridor with one lined with brick. 

What the hell are the roofs of these dungeons anyway? Logically they should be braced with wood, but that would decay (or would it?), so they should be either megaliths or arches. 

Does stone degrade over time (without use, probably not..?) but with use and perhaps dripping water, how does stone degrade? 

What stone would you even expect to be used in construction of a dungeon? Granite is too hard surely? I would expect bricks to be the most practical and affordable and bricks do crumble both from use but also from compression and freeze-thaw over time. 

Does sound echo across marble? How about light? In the Mersey tunnel near me, the roof has been covered with black tar or pitch. it was originally made with a white, reflective, opalescent roof to the tunnel. The idea was that it would reflect the lamps of vehicles and make the tunnel seem more full of light. Two problems; exhaust fumes blackened it, and where that didn't happen the improving strength of electric lights made the roof blindingly white so they had to paint if over. 

But if you were in a classic Carrera-marble tomb, with only lamps, it would be pretty relatively bright surely? There can't be many materials like that. Do we have any idea of the reflective nature of various kinds of stone? Would a difference between slate, bricks or granite slabs add or reduce 10 or 20 feet of visibility?


Viggo Johanson


21 Questions for Empty Corridors 

(This is my attempt to condense the discussion above into a simple set of concrete questions, more for Dungeon designers and DMs, in a style similar to Jeffs ’20 Questions for your Campaign World’.)


1.      Is the air still or does it flow?

2.      If there is airflow, where does it flow to or from, and at which times? (i.e. does it ‘breathe’ in and out as it warms and cools with dawn and dusk like a cave system might?).

3.      Is there moving water? If there is, does it cool the dungeon?

4.      Is it warmer or cooler than outside? Are any parts especially warm or cool?

5.      Are there living things eating, breathing and pooping in the dungeon?

6.      Do the walls sweat? Is there nitre?

7.      Is there a food store? Are there mice or insects?

8.      Is there fire in the dungeon? If so, where does the smoke go?

9.      Is there poop in the dungeon? Where? How strong is the smell?

10.   Is there rot in the dungeon? Are there flies?

11.   Do smells emanate evenly through still air or are they carried by airflow?

12.   If you followed the smells of blood, meat, smoke, spices or poop, where would they lead?

13.   Are their spiders in the dungeon? How stable and old are the webs and where?

14.   Do lichen, moss or fungi grow in the dungeon? If so where?

15.   Are there any sources of LOW FREQUENCY sound in the dungeon?

16.   Are there any permanent natural sounds like moving water or wind?

17.   Do voices, steps or door sounds transmit in a reliable way?

18.   Would the sound of fighting transmit and if so how far?

19.   If someone stays absolutely silent in the dungeon and listens, what do they hear?

20.   Are there obvious changes in construction? Like in materials, methods, age, wear etc?

21.   Do any of the above elements come into play at otherwise contextless choices in which door or corridor to take?



  1. I've been in the Catacombes de Paris. They're nice and cool, especially in summer (14c according to the website). I don't recall many air currents, but there were people always moving about in the tour group to take pictures to make a breeze as they squeezed by.

    I've been in dungeons under castles, and the damp usually correlated with conditions outside. I've even seen one partly flooded. None have been particularly drippy, though dirt floors were sometimes muddy. Sometimes bone dry.

    One thing you didn't mention in the smell section is dirt, and how it smells different in different places. I was particularly struck by just how weird the soil smelt in various ruins and crypts in Rome vs. the UK & France.

    1. I have been all alone in the vaults under the palaestra in Ostia Antica (the ruins of the harbor of ancient Rome) on a hot dry summer day. I remember they were cool but it's been too long to recall if the humidity was higher than above ground. Probably, but I wouldn't swear to it.

    2. Thanks!

      Man, soil is so insanely complicated once you get into it. An encyclopaedia of soil smells would be a lifetime project and sell maybe 100 copies over 100 years. Might still be fun to do though.

  2. I can perhaps weigh in here in the lichen/moss/fungus front. Lichen and moss are both photosynthetic and won't grow without light. That's normal regular world non-magical lichen and moss of course. Fungus is a little different in that it doesn't require light. Most fungi (at least mushroom-forming fungi) are either saprotrophic or mycorrhizal. Saprotrophic fungi feed on dead biological matter, and mycorrhizal fungi have symbiotic relationships with the roots of trees. We can basically rule out mycorrhizal fungi here - even if roots penetrated the dungeon/subterranean habitat it's unlikely that you'd see the fruiting bodies of these fungi as they tend to only inhabit the top layers of soil, and certainly wouldn't be found on exposed large roots. Saprotrophic fungi, however, could certainly be found in a dungeon kind of setting. Most saprotrophic fungi feed in wood, and would want that wood to be damp, and at a temperature of 5-20 degrees Celsius. In a damp environment, with good airflow from the outside to draw in spores, I would certainly believe it possible to see mushrooms on rotting wooden surfaces (doors, door frames, shields etc). As far as I know (and I should stress here I'm merely an amateur mycologist and mushroom cultivator) there aren't any mushroom forming fungi that would feed in dead animal matter. There are, however, several species of pin mold in the genus Phycomyces that grow on dung. Again, if the airflow was sufficient to allow the initial colonisation of spores I'd not be surprised to find pin molds growing on dung in a dungeon. Molds, in general, are likely to be the most frequently found fungus in a classic dungeon kind of setting. And, reflecting on island gigantism, island dwarfism, and other such examples of evolution pushing things to extremes in isolated environments, I wouldn't like to think about the state of a coprophilic Phycomyces mold given a very long period of time to evolve in an isolated subterranean ecosystem.

    Finally I'd like to apologise to commenting as anon here. I'm using my phone and I can't work out how to change the profile to something more honest and amenable to communication. This may be due to the limitation of the phone, of my cognition, or simple the fact it's Friday and I've perhaps had one too many Tina of beer.

    Excellent post!

    1. Who are you, who is so wise in the ways of science?

    2. That was lovely, thank you.

  3. We also went to this place: - which was similar and also gave off heavy dungeon vibes - those two places are probably the closest I have been to something like dungeon exploration. What can I say, we were bored! I think it would be kind of fun to get involved with urban exploration again - there are so many really interesting abandoned places.

  4. Architect here : I have visited some dungeons of various medieval buildings, mostly in summer, and they weren't dripping. The walls could be damp to the touch, and there might be puddle on the earthen floors (mostly by capilarity), but there was not dripy drips. The air, on the other side could be quite heavy with humidity, yet not saturated. As for conventional (yet quite old) buildings basements and underground rooms, natural airflow (as in small holes and cracks, not open doors or basement windows) could not be felt, even though its action on the hygrometry could be observed (over several days). Humidity will be quite even through global osmosis, and only some events (sudden thundershowers, massive intake of humidity in the form of new whitewash, resurging ground spring) would disturb this and produce puddles and drips.

  5. Moss, as anon says, requires light to photosynthesise. But not much light. There is a passage in Robin Wall Kimmerer's wonderful book Gathering Moss which talks of a moss growing in a cave beside a lake in, I think, Canada or the Northern US. The moss does not get any direct light, but for about 10 minutes per day there is a small amount of light reflected off the lake at the right angle to hit the moss inside the cave, and that'll do.

    1. I should have known you would come in with the moss factoids. Disappointed you have no random fungal facts!

  6. This article does not correspond to anything resembling the act of playing DnD. You are lost in theoretical limbo, mind palaces of abstraction, suppositions, intuitions. The replies are similarly telling because they are also not about games. This is a displacement activity for playing DnD. A programmed illusion. A simulacrum.

    How do people determine what direction to go? By the extant geometry, or by random choice. By the phase of the delve they are in. By their remaining resources and the amount of treasure already obtained.. All this processing power, devoted to a theoretical article on what Pixelbitching could possibly be like.

    If this is to be the shape of the supposed Neo OSR (and indeed, NOSR is an appropriate designation) then I shall have to start working on a fitting epitaph.

    1. I'm sorry. I've let you down, and I've let myself down, by thinking publicly about underground spaces in a manner you find impractical. I will take this away with me, dwell on it, learn from it, and hopefully in time I will learn to live with the shame of failing you.

  7. If you want to read one of the sources Gygax drew on for the proliferation of fungi in dungeons, get a copy of Margaret St. Clair's Sign of the Labrys. It's fiction, with a post-apocalyptic setting. It also includes some definite influences on wandering monsters and trapped corridors.

  8. The underground spaces I've been in have mostly been 19th or early 20th century bunkers. Concrete or brick construction in a fairly wet (near the sea) and seismically active environment. Metal (either door frames or exposed rebar) is rusted to an extreme degree and they smelled of rust, rotting concrete/grout (sort of like damp earth but not exactly).

    The thing that strikes me when in an old, unused underground space, but even more building abandoned only a few years before, is the speed of decay and collapse. Hole in the floors, any sort of wood or other organic paneling peeling, collapsing and buckled from water intrusion. Bricks shifted in their courses, red dripping splotches from decaying rebar inside the walls. I think it's much slower with drystone and such, or in dry environments, but in wetter places - especially where salt air gets in or water can freeze, human structures succumb fast.

    The other thing I noticed about such places was that human and animal interactions with them linger. The smell like piss, rats, and old fires. A hobos BO hangs in the stale air for long enough after he's gone for his nest to become brittle with salt and still smell of booze sweat.

    People should think about the spaces they write more. Not because you need any kind of authenticity, but because something other then a maze of bland stone corridors is interesting and fun to play a game in.

  9. I'm a bit late commenting here, but by happy coincidence I first read this article yesterday before going to visit Kaymakli Underground City (an enormous multilevel cave complex carved out of volcanic tuff by ancient Cappadocians as a wartime refuge for thousands of people) today. A couple of anecdotal observations:
    The difference between stale and fresh air was strikingly clear, even for a total novice like me. Most of the complex has good-quality air circulating freely, as it was designed for human habitation with plenty of deep ventilation shafts, but on one occasion I encountered a dead-end passage and the reek of dead air was immediately apparent. I have no trouble believing that adventurers could quickly get good at following their nose in this regard.
    The temperature differential between populated and non-populated rooms was also very noticeable. The layout is such that throngs of tourists cluster along the main marked route, but it's easy to find deserted spaces if you stray from this path, and as soon as you do it becomes markedly chillier (didn't notice any humidity changes, but this may be due to the good ventilation and general dry climate). I'm uncertain as to whether humans could feel these temperature gradients finely enough to detect concentrations of warm-blooded beings from several chambers away, but at the very least, if you step into an inhabited space you're probably going to know about it, even if it's pitch black and silent.
    Would recommend a visit if ever you get the chance, anyhow. Only c20% of the complex is theoretically open to tourists, but thanks to the Turks' bracingly cavalier approach to health and safety, there are multiple points on the lowest public level where the end of the safe zone isn't signposted or blocked off; the passages get narrower and the lights run out but the tunnels go on winding downwards. Proceeding a little way down one of these by torchlight, I found a scrap of paper on which was written "THE TREASURE IS ME I'M DOWN HERE WAITING." I decided I was a little too close to the Veins of the Earth for comfort, and came back up.