OSR: 3 Level 1 PCs Solve 20 Black Doors

Michael Prescott of Trilemma fame crowdsourced 1d20 "black doors" on G+. In his words,
A Black Door is a dungeon obstacle (in Ben Robbins' original West Marches, an actual black door sealed by magic) that clearly separates skilled, versatile, resourceful and powerful parties from less experienced ones. Often adventurers will be completely unable to get past until they return later, having levelled up a bunch or brought special tools or hirelings.
Versatility is fine. Skill is fine. Resourceful is fine. But powerful, well-leveled, and experienced? Not needed. All you really need is a plan.
For a job like getting rid of the drug dealer next door, I'll take a hardware store over a gun any day. Guns make you stupid; better to fight your wars with duct tape. Duct tape makes you smart.
-Michael Westen, Burn Notice (Pilot)

I try not to include explicit black doors in my dungeons. In my opinion, all good OSR problems should be solvable with a very, very good plan and no rolls, or by a lot of rolls and considerable danger. Rolls represent risk - if the PCs are good, they might be able to avoid risk entirely. Looking at an obstacle and saying "not worth it" is fine and sensible, but if the PCs really want to get past an obstacle, there should be a way - without being Level 20 or knowing one specific spell or hiring 30 experts.

Sometimes it works, and a group beautifully avoids a challenge or comes up with another way around a problem. Sometimes it doesn't.

Paladin of Beauty, regurso

Here's a thought exercise; can  a party of 3 generic Level 1 PCs could get through these doors? I've only included doors I like, or ones with enough detail to be interesting.

If the door is too easy, it's not really a challenge. If it requires one very specific tool to solve, or some other equally targeted requirement, it's not worth including. But if it looks difficult to solve but can be overcome with a good plan, your players will be very happy when they succeed. There's no better feeling than "outsmarting" the GM and defeating some impossible challenge with three eggs, twine, and a false mustache.

The trick, as the GM, is to design challenges that can be solved, but not to come up with specific solutions beforehand. Exercises like this help calibrate your design process.

Maybe I'll make a "GM Exercises" series.

Doors and Solutions

The Party

Rolf the Fighter. Kind of big, kind of strong, stupid as a log.
James the Thief. Sneaky, cunning, and can pick locks reasonably well, given time.
Alice the Wizard. Has a pointy hat, the ability to detect magic in a vague and general way, and no spells left.
The party has some standard adventuring gear and very little money. Items required will be listed under each door. I'm assuming the party really, really wants to get through the door.

Door 1

A slab of black granite, positioned like a door but actually built in place. It extends several feet into the surrounding masonry.
Suggested by Michael Prescott.

Solution: The party looks at the slab, pokes the door a bit, tries to find a lever or a switch, and then starts pulling the masonry apart. A giant slab of granite is tough as hell to break, even if they have pickaxes. Masonry has joins.

Items Required: pickaxes and a crowbar.

Door 2

A trap door at the top of a long natural chimney - above it is a room filled with ghouls (dozens) that walk back and forth over the trap door.
Suggested by Michael Prescott.

Solution: Let's say the chimney is 50' high (a pretty decent size for most natural caves). James climbs the walls very slowly with his climbing gear and listens at the door. He informs the party that he hears footsteps. After some debate, Alice and Rolf winch themselves 20' off the ground, tie themselves to the rock, and hold torches away from their bodies. James ties a rope to the trap door and opens it when he hears something step on it. Some of ghouls fall down (they aren't immune to fall damage).

Seeing that there are more ghouls up top, James tries to lure them to jump to their deaths by shouting, "Oh, I'm so delicious today! Look at me!" If that doesn't work, he'll toss a grappling hook at them and try to yank them down, or throw a flask of oil and a torch up there to cause smoke and panic. It's a slow process, but the party is safe.
Items Required: rope, climbing gear. Possibly a grappling hook, oil, and a torch.

Door 3

A 20' section of corridor, the floor is literal lava. It's flowing from a rent in one wall and draining through a wide cracking [into] a chamber below.
Suggested by Michael Prescott.

Solution: Assuming this is generic videogame lava and doesn't cause horribly flash-heating, toxic air, radiant heat, and other problems, the party has a few options. The most obvious is just to briskly walk across while wearing water-soaked boards on the bottom of their shoes. Snowshoes, essentially. Assuming the laminar flow described, the top layer of the lava has a nice thick crust. If it is real-life lava, then this isn't so much a black door as a death trap. Unless the dungeon has a supernatural HVAC system, the entire thing is probably uninhabitable.
Items Required: boards, water, some straps.

Door 4

A door of gnarled and bulbous vigorous oak. Every attempt to chop it causes it to sprout extra thickness.
Suggested by Michael Prescott.

Solution: Fire. Or chisel along the edges and let it blow the door frame open. 
Items Required:
Fire and probably oil, or a chisel.

Door 5

A gale force wind that howls down the corridor extinguishing all natural flames.
Suggested by Ara Winter.

Solution: Let's take the worst-case scenario and make it a 102 km/hr or 63 mph wind. You can walk in wind this strong, but you'll be bent at nearly a 45 degree angle, and it's very difficult to see. Stick your head out a car window at highway speed and look straight ahead (do not do this). This one requires some prep time. After flailing around and losing their torches, the party regroups. First, they find a bucket or another solid container and punch a hole in it. Then they put a lantern inside, pressed as hard as they can get it against the bucket. The lantern will draw still air from inside the bucket and the light will shine out the front. They then take a scarf and lash a bottle or potion flask over one or both of James' eyes to make an improvised set of goggles. So equipped, and stabilized by his two friends, James can move up the corridor, scanning his lantern from side to side to check for traps. 
Items Required
: bucket, lantern, glass bottle, scarf.

Source unknown

Door 6

The opening in the top of the chamber is smooth and slopes upwards, like a reverse whirlpool. Acidic oozes drip along the surface.
Suggested by Jesse Cox.

Solution: This depends on the height of the chamber. If we're being generous, a ladder can reach the top. The party needs a ladder and two poles. While James and Alice stabilize the ladder from the bottom, Rolf climbs up, keeping himself off the walls with the two poles. Presumably there is a trap door or a lip at the top. If the chamber is higher or larger, the party builds a bonfire and tries to smoke the oozes to death, then climb the walls. It might not work but it's worth a try.
Items Required: ladder and poles, or firewood.

Door 7

A sphere of annihilation blocking a corridor. On the ground nearby, many skeletons missing a head or arm or more.
Suggested by Eric Nieudan.

Solution: Sighing, the party gets out their pickaxes and starts going after the masonry again. At least this time there is a built-in disposal facility. It might be easier to check their map and see if they can tunnel around from a different room.
Items Required: pickaxes and a crowbar.

Planetarium Time Clock

Door 8

An aquarium, positioned like a door. It is filled with water and anti-pufferfishes (they are full of explosive gas that ignites as soon as they are not in water anymore). One glass pane is super thick and can be drilled while the one on the other side will shatter as soon as it is hit or pierced.
Suggested by Jean-François Lebreton (Jarnos).

Solution: I'm assuming the PCs know what an anti-pufferfish is, or at the very least are deeply suspicious. If they approach from the thick side, they poke the glass, determine it is thick, drill a hole (or chip one with a chisel, more likely) and let the water drain while running away. Slowly approach to check on the water level. If they approach from the thin side, poke the glass, determine it is thin, then shoot it with a bow and arrow or chuck a rock at it and run. All you need is 1 anti-pufferfish explosion to clear all the rest of the anti-pufferfishes. This is practically a self-opening door.Items Required: hammer and chisel, or a rock.

Door 9

A door of living wood that grows thorny arms and claws to tear the flesh of anyone who comes close.
Suggested by Eric Nieudan.

Solution: Fire. Or if that's too boring, throw a cow or a goblin at it and open the door while it's distracted.Items Required: fire and probably oil, or a cow, or a goblin.

Door 10

A door rooted into the living rock around it, made entirely of a solid plank of magically treated trollbone. Any attempt to penetrate it rapidly spawns one or more angry, confused trolls with (healing) wounds from the tools. Meanwhile the door itself heals itself from the power of the mountain and borrows the rock's invulnerability to acid and fire.
Suggested by Evan Edwards.

Solution: This isn't a door. It's treasure! Infinite free trolls. Just find a way to tame or bribe them and you'll be king of the world.

More seriously, this one would stump the party (assuming they dealt with the trolls). The only solution I can think of is to feed the door milk and soup until it gets so fat it bursts or opens out of sheer contentment. Alternatively, tickling, or a cold bit of ice at the bottom of the door that convinces it to shift.
Items Required: Milk and soup, maybe a paintbrush.

Door 11

A reverse gravity spell that makes you fall onto the stalactites at the ceiling, 100+ ft above.
Suggested by Eric Nieudan.

Solution: After sensibly throwing a rock into the room first, the players tie a rope to something, descend "up" the wall, walk across the ceiling, and climb back up the other side, chucking rocks every few feet to ensure there are no un-reversed pockets.
Items Required: Rope, climbing gear.

Faberge Fractals, Tom Beddard

Door 12

The veins of metal collect here into a single polished mirror. Anything that goes in instantly comes out. Any spell or object thrown, any individual that goes in walks right back out. Any mirror carried through is instantly rendered opaque.
Suggested by Evan Edwards.

Solution: Alice the Wizard suggest prying the mirror from its setting and forcing it into itself by bending it in half. Crowbars and many hours of work will be required. If it doesn't bend, great! It's easier to get off the wall and get behind. If it does bend, a paradox might ensue, but that's good too. Alice the Wizard has no scruples about causing magical disasters in the pursuit of loot.
Items Required: Crowbars, chains, strong backs and weak minds.

Door 13

A frictionless corridor that gently slopes upwards. 80' long.
Suggested by Michael Prescott.

"Hey," James says, "remember that gale-force corridor a few rooms back? What if we redirect the air flow..." Alternatively, climb the walls. It's tedious, but you can't fall to your death.
Items Required: Climbing gear.

Door 14

A 40x40x40' room; the entrance is a small round opening in the dead middle of the ceiling.
Suggested by Michael Prescott.

Solution: It might take a few trips to the surface, but the party can build some decent scaffolding.Items Required: poles, rope, and patience. Alternatively, Door 4, popped out of the wall.

Door 15

An earthquake has caused the stone to shear - a 10' wide corridor has been offset by 9'10" leaving only a two-inch gap.
Suggested by Michael Prescott.

Sighing, the party gets out their pickaxes and chisels again. All they need is a gap big enough to crawl through sideways.Items Required: pickaxes and a crowbar.
 Field for the British Isles, Antony Gormley

Door 16

100' corridor ends in a room. In the room is a crackling metal globe on a post. Occasionally, lightning cracks off the globe and hits the wall of the room. It also zaps the nearest thing in corridor with lightning once every five to ten seconds.
Suggested by Michael Prescott.

Solution: After a good zap, the party considers their options. If the lightning target any thing, they will push something ahead of them - a bucket, a stone, a barrel - with a 10' pole. If it targets the nearest living thing, it's time to organize a stampede of goblins, cows, or rats in a sack. This might require some prep work and a bag of spare rats (to get back).
Items Required: Something to push that can survive multiple lightning strikes and a pole, or a stampede of living creatures.

Door 17

100', pitch dark hallway of trip wires and pits ends in a door with a detailed demonic face twisted in rage. The door causes fear in any who lay eyes on it - the power of the fear is greater the more clearly the face can be seen. When dim torchlights merely brush its shadows, it's just a sense of imminent and growing doom, but in full light the intricate details of its horrors can be seen and inspire a panicky flight in those who behold it.
Suggested by Jesse Alford.

Solution: The party, being sensible, disarmed the tripwires on the way up, and their first panicked retreat back wasn't deadly. Assuming they figure out it is an irrational magical effect, they regroup and approach a second time. The last few traps are disabled with their eyes looking downwards only. The door is checked by thwacking it with a pole a few times while looking away, and then opened by Rolf while also looking away. 
Items Required: Nothing specific.

Door 18

Reverse door: The treasure mcguffin / thing you've been sent to recover can be reached with relatively little difficulty, but it is mystically tethered to the room or the dungeon, impeding your escape. This could manifest in a few ways.

The object grows in weight with each step you take. Its weight is tracked per person based on how many 5' or 1m squares they travel with it item while in the dungeon. [...] [Or] there is a literal tether attached to it, but you can only see it with detect magic / see invisible or similar. It can't be broken by brute strength

Suggested by William Altman.

Solution: If the object grows in weight, carefully chart the shortest path and drag it the last few hundred feet to the surface with some pulleys and horses. Tell their client it's ready for them to pick up. If it's any heavier, the party won't be able to move it with mundane equipment. Instead, they drag it as far as they can, then set up camp to see if anyone comes along to put it back. If someone does (presumably by disabling the enchantment), they pop out of ambush and try to run away with it.

If there's a tether, figure out what it's tethered to, and get the pickaxes ready. The tether can't be broken but one end of it can, and you can probably drag it to the surface as well.

Items Required: Horses and rope, or an ambush spot, or pickaxes. 

Door 19

The corridor is split by a ravine 18' across. The inner walls of the ravine are soft and porous, and crumble easily.Suggested by Michael Prescott.
Solution: Depending on the depth of the ravine, climbing down and back up might be possible. Alternatively, if one PC can get across on a bridge made out of three ladders tied together, they can find something to tie a rope to and create a simple rope bridge. It's dangerous but feasible.
Items Required: Climbing gear, or 3 ladders and some rope.

Door 20

Giant stone golems surrounded by anti-magic cloud.
Suggested by James Shields
The PCs are too poor to worry about antimagic fields. Their main advantage is stealth and speed. Giant stone golems are slooooow...
Items Required: Good boots.

Roman Farmer's Calendar

Doors I Don't Like, And Why

Personal opinion only, your mileage may vary, etc.

Door I-A

An open archway, flanked by silent statues, gazing down on the path between. Anyone who passes between is vapourized by energy beams fired from the eyes of the statues. (Lifted wholecloth from The Neverending Story.)
Suggested by Adam Drew.

Door I-B

A small labyrinth where the dead ends are formed by grills of heavy iron bars. Deadly oozes move through them unimpeded, and take the shortest path toward living creatures.
Suggested by Michael Prescott.

The only way to find out how the trap works - or even that it exists - is for someone to die. By the time the players understand the trap they are dead. That's boring. With the ooze example, there's a chance - a slim one, but a chance -to figure things out by listening and moving carefully, but the statues are just arbitrary death.

I don't mind "Save or Die" effects. One of the first traps in my tutorial dungeon is a PC-slaying hammer. But the PCs can find it beforehand. There are clues. They have a chance. 

Door II

A small, naked -- androgynous and neuter -- humanoid figure with mayfly wings and glittering white skin sits in a diminutive high backed velvet armchair reading a book. Calmly addressing the party, it looks at them with black, void like eyes and speaks in a hauntingly beautiful voice, "Welcome. I am the door of black. Do you have my key?"

The book and chair are illusions, and the powerful fey wields unlimited spheres of annihilation in the same way a child would throw rocks, plucking them out of thin air. If attacked, the first action is to simply eliminate the weapons used and calmly respond, "No, young one, that is not the key."

Suggested by Evan Edwards.

I don't like "guess what the GM is thinking" puzzles, and this is a classic example. Unless there's clearly a key somewhere - and there's some thematic link or purpose - this is just an excuse for frustrated players, a bored GM, and a 2hr pointless discussion with a fairy in a chair. 

There are also better ways to "punish players for being stupid" than an invulnerable, all powerful NPC. Conceal your lessons behind gameplay, not behind mouthpieces.

Door III

An empty stone arch sits at the bottom of the dungeon, rune-rimed and inert. Ancient writing covers the walls, describing a ritual, a portal - but those who study them are compelled to leave.
Suggested by Jesse Alford.

I also don't like compel-type effects. They always seem lazy. Players have lots of stuff they want to do. If you, the GM, want them to do something, give them some good reasons. Don't just say "you must do this because of magic." It makes choosing to do anything feel cheap. As an offensive ability (like charm person) it's fine, but a magical compulsion just sitting there feels like you couldn't come up with a better reason for something to happen.

If you want players to grab the shiny stone at the bottom of the pool, don't make it magically compelling. Give them other reasons.


  1. A bit of context: The Fey one that you didn't like (Door II) was a response to a comment that most of these aren't obviously non-approachable obstacles and would result in certain type of parties banging their heads against them assuming they were missing something. It was also a "okay, how can I do a door that's not literally a door." I'd agree it's certainly an incomplete one, with the GM providing the tie in to the dungeon. In the right dungeon and with the right group it works. It's certainly weaker than the other two I added, mostly because of the two constraints I set up for myself when making it, and not a drop in dungeon element like most of the others.

    In the incomplete form, or as a generic drop in, I don't like it either. It's more of a concept to use that addresses the perceived problem than a finished door.

    (My name is Evan Edwards, not Edward Evans.)

    1. And I'm gratified you spotted the same weaknesses with it that I didn't like. Outside of fiat and a GM proxy voice, the only direct way to deal with a table that doesn't understand the concept of a black door is over the table talk, ideally between experienced players and less experienced ones, and then falling to a GM reminder that not all encounters are calibrated to where the party is at any given time. Direct communication is my preferred method over either GM fiat or NPC theater.

    2. Oh yeah, no worries there. I wasn't posting it as an example of "Durr hurr hurr, Evan Edwards can't design things." It's a good bad example, if that makes sense, and that's a valuable thing. There's a context where it works, sure... but without that context it's a really good example of what not to do.

      (Also, I put everyone's names as anagrams. It just so happened that, aside from yours, the anagram turned out to be identical to the original name. What are the chances?)

      And direct communication is good, but there's a 3rd option: implicit tutorials. You don't need to have an NPC say "To pass the door guarded by me / you guys must at level 3" or have a magic effect that does the same. You can put sneaky threats, distance, or more tempting targets first. Steering without appearing to steer is fun.

  2. I don't know that any solution that requires dismantling masonry is a realistic solution to the problem in an OSR dungeon, because in most OSR dungeons, there is a punishment for poor use of time and also for making too much noise in the form of random encounter checks. Have these three first level adventurers murdered everything in the section of the dungeon they're currently in already, such that there are no random encounters that could interrupt them?

    (I know I'm challenging the basic premise of your post here, but despite that I really love you blog. It's one of my favorite recent finds. Also I'm not really meaning to challenge so much as clarify. )

    1. So OSR games are all about resource trading. You trade HP for progress or treasure by fighting, you trade light and time for exploration, etc.

      Sure, spending 2 hours demolishing a wall isn't always going to be feasible. It's not always going to be safe. But if the PCs *really* want to get past the wall, they'll find a way, and either run away from the random encounters, fight them, or find a way to circumvent or use them. After all, the local goblins might know how to get the door open.

      The situations above are for PCs who are determined to spend all their resources to overcome an obstacle.

  3. Probably *really* missing something here, but...
    Door 13, "A frictionless corridor that gently slopes upwards. 80' long."
    Tie a rope to the thief. Body-slam him hard, sending him like a shuffleboard puck up the slope. (Skee ball?) He can grab onto whatever's next, or perhaps slam a spike hard into the ground and work from there.

    Did the author mean *infinite* friction? So, like, one of those dreams where you try to run and can't move an inch?

    1. Where's a high-school physics student when you need one?
      Look, if we assume a 10 degree slope, we can figure out the angle. We can then figure out the force required to push a person up the slope easily (overcoming gravity + air resistance).