This article was first broadcast in Episode One Hundred Sixty Eight on 9 July 2021.
Ryu (attacking): All right, hands up and drop everything you’re carrying or I’ll paint the walls with…oh. Hi Tony.
Tony (nervously): Hi…is there a reason I was almost murdered?
Ryu: I just thought you were staying in the recording booth. Confused you with someone else.
Tony: Don’t tell me who they are. I probably already know too much. Also, how did you sneak up on me like that?
Ostron: How high is your wisdom score?
Tony: You don’t get to be a good lawyer if you can’t spot people lying through their teeth, eyes, or whatever other body part and I’m a pretty good lawyer.
Ryu: Okay, so your perception is probably good too, but I mean…I’ve got the carpeting in the recording booth, all the ambient noise around, and of course there’s the hallways.
Tony: What hallways?
Tony: I’m lost.
Ryu: No you aren’t.
Tony: I really think I am.
Ryu: You can’t be; no hallways.
Tony: Okay objection! Nonresponsive!
Ostron: No she’s actually right; the Guild house bucks the trend of D&D architecture.
One thing that veteran dungeon delvers, cave crawlers and fortress infiltrators know is that when you enter an enclosed space where monsters, malingerers, or mad beholders are living, you’ll probably be dealing with a lot of rooms connected by narrow, winding corridors.
In some few cases these corridors make architectural sense. Castles, for example, are full of restrictive passageways for defensive purposes; if you have a hallway that’s only wide enough to fit one person through, it doesn’t matter if the attacking force has five people in it or 500; the defenders still only have to deal with 1 person at a time.
But any geologist or avid caver can tell you that water and magma generally don’t flow through rock like strings of beads, creating five foot wide corridors that suddenly open up into oval caves fifty feet wide. It can happen due to changes in rock formations and the materials in the ground, so you might get a thin stretch of cave for a while, but they don’t often start looping back on themselves. And your local dwarf will tell you mining out a huge room for materials and then digging a really long, very small tunnel to the next seam is a bad idea for a whole host of reasons. So the obvious question is; why are they in most dungeons?
The reasons are almost purely mechanical and directly tie into gameplay rather than realism. The Exploration pillar of D&D or any game really relies on there being some sort of tease involved. One of the thrills for a lot of people in an open world video game is the idea that they can see a huge mountain or a strange monument in the distance and then actually go visit whatever it is. Now, you usually can’t have sweeping vistas when exploring a cave (unless you’re in the Underdark because the caves down there are stupidly large) so you won’t be able to provide something neat looking in the distance to convince your players they should trek the 300 yards or meters to go find out what it is. But what does often spark curiosity is a nice, long, dim hallway.
Now hallways today serve a slightly different purpose than they did in the early days of D&D. Up through possibly 2nd or even 3rd edition there was a different focus to a lot of dungeon delving. On the face of it, whether you admitted to yourself that it was your primary motivation, or you remained adamant in your belief that farmer Rogers’ 17 year old cow with three legs is enough a promise of reward to convince you to go into a cave filled with half rabid demon worshipping ogres, the practical expectation was that you were coming out of that cave with a lot of loot. There would be weapons, jewels, cutlery made of rare earth metals, half a gallery’s worth of art, and just straight up gold.
However, going back to those early editions, light is a major problem; comparatively few races had access to darkvision and everburning torches were less of a common commodity, so everyone had to bring mundane torches. Those took up room in everyone’s limited inventory (because tracking encumbrance was a thing people did back then too) and they only lasted so long. All of the hallways served 2 purposes related to that; they extended the amount of time adventurers would have to spend in the dungeon, meaning they had to consider the limits on how long until they ran out of light, and they provided long stretches where it wasn’t possible to see from one end to the other, even with torches.
Nowadays the hallways provide different challenges with exploration. They can extend the length of time it takes to travel in a dungeon, which may be a factor if there is some sort of time limit the characters are working against, but mostly what they do is give the characters decisions to make and obscure the structure of the dungeon.
In 5th edition, having more than a couple characters without darkvision is more unusual than having characters with it, but no character races have tremor-sense or ground penetrating radar vision. So rather than a long dark hallway obscuring the path because of darkness, a hallway that ends in a T-junction works just as well for keeping the characters from seeing what’s ahead.
In addition to keeping characters from seeing what’s ahead, the hallways can also obscure exactly what direction is actually ahead.
This is where exploration comes in; the more options there are for travel, the more the characters might need to search through to find their objective. It is still possible that they’ll make all the right decisions and drill through the dungeon like the final room has a tracking beacon in it, but even if they do that, or if the area just has a long corridor with a large door at the end that literally or metaphorically has a “the thing you’re looking for is in here” sign, there will be some members of the party that will probably get curious about what’s in the adjoining rooms and offshoot corridors. Enticing them to go down those other corridors is a matter of making sure there are interesting things at the ends of them, whether those are alternate side quests, extra sources of treasure, or secrets that can help them proceed through the dungeon they’re in or add more information that pertains to the larger campaign they’re going through. If there aren’t those sorts of things at the end of the corridors, very quickly the characters are going to be more annoyed by the extra corridors than interested in them.
One thing that the corridors have done both originally and in modern times is acted as a buffer for the enemies. There are usually multiple groups of enemies present in the dungeon and while individual groups of them are challenges for the party, in most cases all of them showing up at once would probably result in rampant character death. As anyone who’s visited an old castle or even just stood in an empty hallway where the walls and floors are some form of rock can tell you, even the littlest sounds are amplified and carried along by the echo. The sounds a full-scale battle make are definitely going to carry, and possibly alert other occupants of the complex to something going on. The fact that they have to traverse the same corridors the characters eventually will means there’s a realistic reason for some time delay before the reinforcements arrive. And depending on the structure of the hallways it may also mean they trickle in rather than arriving all at once in a mob and suddenly double the number of enemies.
Tony: All right I’m tossing out another objection for relevance? I still don’t understand how any of this relates to Ryu sneaking up on me.
Ostron: Hallways would mean she can’t sneak up on you, or at least not as easily.
For situations where the adventurers want to avoid being detected, hallways can make their job that much harder. The official rules as written state that out of combat, someone moving while trying to hide can progress 20ft per round, however they also have to make a stealth check prior to that to determine exactly how stealthy they end up being.
Obviously DM’s can and do play around with those rules a lot because it can get tedious fast if the characters are progressing through a large dungeon. Some only require one roll if the character is proficient, or allow the roll to stand until or unless the character does something different (requiring a new roll after they pick the lock on a door or check for traps, for example).
Hallways make all of that more difficult. First of all, it’s more distance to travel, so that slows progress and means that the Paladin with two left feet wearing plate mail will have to make extra checks. Or the group has to deal with the risk of sending a scout fairly far ahead of the group, possibly out of sight and/or out of range for a quick intervention if they run into trouble.
Running into trouble is more of a risk in hallways as well. If a stealthy character is skulking around in an average room and someone happens by they have a decent chance of finding a drapery or some piece of furniture to hide behind and unless it happens to be a mimic they’ve got a good chance of staying concealed.
The Mimic: Best part of my day!
Ryu: I thought Lennon was off meeting with his patron?
Tony: Is he back early? Because as much fun as having my life threatened is…
Ryu: I don’t see him…anyway never mind.
The point is that if your sneaky scout is making their way down a plain hallway, their options for staying hidden are limited to say the least. About their only hope is doing that thing where they get up to the ceiling and brace their limbs on all the nearby walls and let me tell you that is not an easy acrobatics check.
So how does any of this help your average DM? Well obviously if you’re someone who likes to design their own dungeons, it’s helpful to know what mechanical effect hallways are going to have. The more your dungeon looks like an MC Escher painting, the longer it’ll take the characters to move through, the harder it will be for them to sneak, and the more tactical and exploration decisions they’ll have to make. Keep in mind that they’ll be fighting and searching through rooms too, so if you already have a dungeon with 12 different major areas of interest, putting 500 yards or meters of extra tunnels in there may not be the best idea unless you intend for them to be there a good long while.
Also, even if you don’t have any geologists or architects in your gaming group, if you are putting a bunch of tunnels in it’s a good idea to figure out why they exist. The easiest explanation is if it was a constructed area, like catacombs or a mine, and it was later modified to be more defensible. As already mentioned, castles feature longer tunnels for defense, and that can extend to any building built with that in mind; even some modern government buildings have architectural features focused more on defense than aesthetics.
If it’s a completely natural area, fortunately nature can lend a hand. We described how variations in rock can form naturally narrow tunnels. That won’t create a winding maze but it can explain some of them. Others can be the result of D&D creature activity. Kruthiks and Umber Hulks leave narrow tunnels through rocks all over the place, and if you need a passageway that’s slightly larger, the purple worm can help you out. The good thing is those creatures don’t have to be around to make them; they could have come through 30 years ago and the tunnel will still remain, just waiting for a modest Nature or Stonecunning check for someone to figure out why it’s there.
Now if you aren’t a cartographer yourself and prefer to have your maps put together by someone else, all of those details are probably going to be provided for you. However, you should still keep the mechanical implications in mind for the same reasons. Pulling out a map that resembles a ball of yarn is going to keep the characters occupied for a long time, so it may not be the best idea if you’re hoping for a quick, one-session crawl.
Ryu: You all squared away about the corridors now?
Ostron: Actually come to think of it…always talk about defending this place, why don’t we have corridors in place for defense?
Ostron: What, is someone going to bring legal action because it’s too far to run down the hallways if the building catches fire?
Tony (didactically): Well, in many jurisdictions, the lack of fire escapes within a certain distance of…
Ostron: Forget it, do you know how many of us can cast “create water”?
Ryu: No, it’s that the slime trails only reach so far. It still complains about how tightly the hatch to the Audio alchemy cave shuts, but oddly Mikey isn’t interested in doing anything about that.
Ostron: I really don’t think that’s a better reason.
Ryu: Speaking of, it doesn’t look like there are any slime trails heading into the Scrying Pool, so we should probably take care of that ourselves.