One of my perennials is a kludge of 3LB OD&D with Chainmail filling out some of the lacunae it was clearly meant to fill. It doesn’t draw anything from later editions. If I can’t find it in OD&D or Chainmail, I just make something up. The resulting mess is what I use for Faz. These are the rules for basic Underworld matters like doors, lighting, etc., which are just expanded a bit from the original rules in The Underworld & Wilderness Adventures.
The Underworld is Chaotic and while it recognizes its own, it is supernaturally opposed to incursions from the surface world. The air is thick and miasmal, the portals are obdurate, and every corridor, grotto, and nook is pervaded with a sovereign tenebrosity which bedevils delvers without bothering the Underworld’s own partisans in the slightest. The stone itself resents the presence of outsiders so that treading the labyrinth is a miserable slog.
MOVEMENT IN THE UNDERWORLD
All distances in the Underworld are in feet rather than yards. Whenever a distance is indicated as inches, convert it to feet, with 1 inch equaling 10′.
Underworld movement, quite slow by the standards of the upper world of sanity and light, is measured in 10 minute turns. In 1 turn, a figure can move twice, so that a light footman could move 240′ in 1 turn. This movement rate assumes cautious exploration with mapping, cursory inspection, and so on.
Time spent on active searching, loading treasure, focused hearkening, employment of the ESP spell, and so on will slow movement as determined by the referee.
If fleeing or otherwise abandoning circumspection, a figure can move four times per turn, so that a light footman expeditiously buggering off could move 480′ through the Underworld in 1 turn.
[My current encumbrance system is basically deciding if a character is Light Foot, Heavy Foot, or Armored Foot, then eyeballing what it’s carrying and moving it a category up if it seems appropriate. Very precise methodology.]
Secret passages may be located through active searching on a die roll of 1-2. Elves locate secret passages on a referee die roll of 1-4 rather than the usual 1-2 for other characters. Even if not actively searching, an elf passing by a secret passage will sense the presence of something odd on a referee die roll of 1-2.
Underworld doors are peevish and do not open for delvers by a mere push or turn of a handle. They must be forced open, with a die roll of 1-2 indicating that the door opens; smaller, less effectual characters like hobbits may require a 1. Up to three characters can attempt to force a door at once, but any characters engaged in door-opening are ill-prepared to bring themselves quickly to bear against menaces on the other side.
Open doors will, if given the chance, redress their grievances by slamming shut at the first opportunity. They can be wedged open with the iron spikes ubiquitous in delver supply shops, but on a die roll of 1-2 will contrive a method of closing anyway.
On the other hand, doors will cheerfully open at a touch and stay that way for Underworld dwellers unless held shut or otherwise barred.
Underworld traps are fickle and unreliable, triggering as intended on a die roll of 1-2. Unlike doors, traps find both delvers and Underworld dwellers to be equally aggravating and will, if their caprices are suitably tickled, unleash upon either faction.
The Underworld is dark, and not the sort of darkness that gimlet-eyed little strivers can pierce with keen night sight or the like. Either a light source or the infravision spell must be employed if delvers are to see.
There are two main methods of illumination available to delvers: torches and lanterns. The torches and lanterns typically purchased for use on Underworld delves are manufactured by dwarves and Martians respectively and are both affordable and well suited to their specialized purpose.
Torches offer reasonable illumination out to about a 20′ radius, beyond which it is difficult to see much at all. A torch burns for about an hour, more or less, and will usually not go out if exposed to a breeze or dropped for a moment in a puddle. Dwarven torches put off relatively little smoke and soot; nonetheless, they are not considered ideal as primary sources of illumination for a delve, although they are undeniably useful when circumstances call for the targeted application of open flame.
Martian hand lanterns are peculiar oil lamps generating a gas which burns without a wick. They illuminate well out to about a 30′ radius and less well for a bit beyond that. Furthermore, a cunningly crafted lens allows the projection of a beam twice that distance and illuminating a 10′ spot. These lanterns may be quickly shuttered without extinguishing the gas within and, because they do not use a flame, are not undue hazards if dropped or shattered. For a nominal fee, a lantern may be refilled to last for the duration of all but the longest delves. Accordingly, they are quite popular.
A character may theoretically fight with a torch in one hand and a weapon in the other, although doing so in narrow corridors while flanked by comrades may prove less than practical. It is virtually impossible to fight while holding a lantern; for the sake of game play, it is generally assumed that the lantern has been quickly placed somewhere out of harm’s way, although certain spells and effects may disturb it in the unlikely event that the referee remembers. To be on the safe side, judicious delvers generally secure the services of at least one link-boy so that, barring his gruesome demise, such matters need not trouble them.
Those delvers determined to tote around flammable liquids may purchase lamp oil. Note that this substance is not specifically developed for weaponized uses – typically the target must be doused, then open flame must be applied. Such instances will be adjudicated on a case-by-case basis, and will obviously work to some effect if pulled off. The author notes that there are probably reasons that the annals of heroic man-to-man combat are not replete with tales of short-range indoor Molotov cocktail deployment.
AREA EFFECT SPELLS
It is axiomatic that delvers will cast spells of spectacular concussive effect in tightly enclosed spaces. This must be handled as it arises, but in general the detonation of fire balls and lightning bolts in insufficiently capacious venues will end poorly. Or very well, depending on one’s attitudes towards depilation, deafness, and epidermal integrity.