On Completeness

Here be Dragons

Over the years there have been a lot (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18) of discussions about crunch vs rules lite and where folks preferred points are on the scale.

In these discussions, I frequently see folks conflate crunch (or mechanical weight, or similar) with completeness.

To give a (personal) definition, if you are directly following the rules and wind up in a situation that the rules do not cover, the rules are incomplete. The less this happens, the more complete the system is.

Examples

Light

In all versions of D&D, you typically pack light sources (torches, lanterns, etc). These are a limited resource, and we’re told explicitly that we can run out. What happens when we’re still deep in a dungeon but we run out of light? Undefined.

Encumbrance

In AD&D 1e, we have a detailed encumbrance system. Each player can carry a certain amount of weight based on their strength. Armor, weapons, and some pieces of equipment are given weights. First party modules have a nasty habit of not including the encumbrance value of treasure (how much does that 12” solid silver statue weigh?). Containers are given weights (so carrying a sack weighs you down slightly), but not capacities. We’re told that a small sack costs 10c and weighs 0.5# and a large sack costs 16c and weighs 2#, but never told how much weight either can carry.

This further extends to vehicles. 1e prices out horses, mules, carts, and wagons, but doesn’t specify how many horses are required to pull a wagon or how much treasure can be loaded on a cart.

It’s interesting to contrast AD&D 1e here with B/X or OD&D. 1e has a (deserved) reputation for being more crunchy, but is often (like here) less complete. OD&D and B/X give that carried adventuring gear combined weighs 8# (which is a lossy but complete abstraction), and each give carrying capacities:

BX B20

BX X10

OD&D vol 1, p15

Food

In all versions of D&D, adventurers must eat (and so typically pack rations). None of the original three games (OD&D, B/X, or AD&D 1e) specify what happens when you don’t eat. The closest we get is X51, which says:

Characters who run out of food may face a variety of circumstances that must be handled by the DM. Possible effects of hunger might include the need for more rest, slower movement rates, minuses "to hit", and gradual loss of hit points.

Similarly, horses (and mules and whatnot) must eat. Animal feed is never given a price or weight. If horses are supposed to be able to feed themselves for free (via grazing), this is never said. Per acoup:

The small native ponies of the Steppe can subsist entirely off of grass, but the sort of horses available in the agrarian world are bred too big and strong to eat entirely grass. Their nutrition requirements are too high and so they require feed, at least some 4.5kg of it per day assuming local grass is available along with time to let the horses graze it (during which the wagon is, of course, stopped).

Sleep

In all versions of D&D, adventurers must sleep. None of the original three games specify what happens when you don’t sleep (other than being unable to prepare spells).

Fleshing it Out

For light, there are a couple of ways out. Hopefully the party has at least someone with darkvision or infravision, and then that PC can lead everyone out. If combat arises, use the rules for blindness (unable to attack in BX, -4 to hit in 1e). I also recommend players carrying a handful of candles, so that they can still have some way of getting out with poor light. If all else fails they can describe a strategy like “follow the left wall” and then we penalize their movement to ~30ft per turn and roll random encounters normally.

For Encumbrance, I recommend fleshing out encumbrance values for items, and capacities for horses, containers, and vehicles. Delta’s are well researched, so feel free to copy his homework. (1 stone = 10lbs).

For horses, I recommend using acoup’s recommendation; a horse (or mule or whatever) requires 10lbs of food per day.

For lack of food and sleep, I recommend a simple fatigue system:

• Light: Disadvantage across the board. Effects all dice rolling concerning your character, including attacks against you.

• Heavy: Disadvantage across the board. Effects all dice rolling concerning your character, including attacks against you. Reduced to half movement speed.

• Exhaustion: Disadvantage across the board. Effects all dice rolling concerning your character, including attacks against you. Reduced to quarter movement speed. Reduced to half HP.

This is intentionally punishing but not lethal. Disadvantage means roll whatever dice you’d normally roll to see if you’d succeed twice and take the worse result. It’s nice because it works in whatever game you’re playing, with whatever dice you’re trying to roll (d100 thief skills, d20 attack rolls, d8 damage rolls, etc).

Recover fatigue by addressing the underlying cause: get some sleep, eat some food, etc. Fatigue stacks.

In general, when reading through a TTRPG for the first time it’s good to try to notice gaps like these, so you can patch them with research or by importing a system from another game (and telling your players about it) rather than by scrambling to make a ruling mid-session.

When writing or editing a new TTRPG, the same applies. Check to see if you’re directly implying an undefined game-state, and then define it. At the laziest, you can always do what Moldvay did with food, and let the GM know that they’ll have to make their own ruling. Knowing that there isn’t a rule is good; it lets the GM know that they can stop looking for one.