10 Reasons Why the Guild has a Partial Map

His Majesty the Worm advocates for the GM to give the players a copy of the dungeon map. In my opinion, this is all positives and practically no negatives. 

But of all my good and time-tested advice, I've seen gamers balk at this frequently. "Why would the adventurers have a map and not know what's in it? How could the players possibly have a map and the dungeon not be conquered?"

As much as I beg on bended knee "Don't knock it till you try it," I wanted to give you some options for the flavor behind why the players start with a (mostly) complete map of the Underworld.

1. Legacy documentation

The map was made by the guild, but the original guild founders are no longer members. They died or retired, and the guild continues like a Ship of Theseus or an old band. The current members still have the legacy map, but don't have any descriptions of what each room contains (just a stale Jira ticket marked "Next sprint" from the original cartographer). And certainly, the original guild members didn't find every secret door or trap.

2. Watercooler talk

The map doesn't belong to any single adventuring guild, but is part of the collective learnings of each guild in the City. At the taverns, they swap stories about new sections uncovered, new passages that have recently opened, and everybody's maps are updated at the speed of rumor. A table in the back corner of the Tavern of Lost Loves has a map scratched into the wood, and serves as the single source of truth for each guild to update their maps.

3. Spell

There's a relatively simple spell called "Magic Map" that conjures a map of any building or underground level the sorcerer is currently in. Practically speaking, any sorcerer could get the reagent and cast it as they travel. But, luckily, this work has already been done for them for all discovered dungeon levels. It's easier to just trade the a few coins to get pre-conjured maps before descending.

4. Cartographer's guild

The hard work of mapping the Underworld is done primarily by the cartographer's guild. Buying their latest updates is just part of upkeep.

(Any of the other mapping technologies in this list might be employed by the cartographer's guild.)

5. Psychic snails

It's well known that psychic snails will chew patterns in moss resembling crude maps of their immediate environs. Guilds make maps using these trails.

6. Bat lore

The bats of the Underworld are acquainted with the nooks and crannies of each level, mapping them methodically using their sonar. They're willing to trade these impressions to (demi)humans in exchange for certain narcotic sounds, for meteoric iron, and for dream honey.

7. Ancient history

The Underworld is newly come to this iteration of the City, but it is by no means new. Each layer of the Underworld is a stolen civilization: a previous City pulled underground by His Majesty the Worm. There exists reliable records of these ancient Cities. Go to the library and read these maps. You can see their basic outlines reflected in the labyrinths below. 

8. Mall maps

The Underworld provides you with a map of itself, like a shopping mall does. "You are here" it reads, on certain obelisks and plinths throughout the Underworld. 

9. Daemonic revelations

The Tower Gnostic conjures and tasks genii (spirits of a place) with mapping the mausoleums, grottoes, and fountains that they call home. Such work is subsidized by the City. The maps are distributed to guilds upon the signing of their guild charter; it's the reason they pay taxes.

10. Earth elemental haruspexy

Earth elementals look like charming old men made of stone. However, the shape of its intestines are reflective of the caverns they call home. Take an earth elemental into the mouth of a cave and kill it. Disembowel it and study the pattern of its entrails. Make a map from the results.

---

And if all of the above is unsatisfactory, maybe you'll get a kick out of making a scratch-off map.

Design thoughts sidebar

In the early iterations of Worm, I used the "Spell" explanation above. But there were problems with this: when the players went into a new section of the dungeon, preparing the "Magic Map" spell was a non-choice--they always did it. And once they had the map of that level, it was never a choice to prepare--they never did it. Making non-choices felt like bad game design. 

Then I realized: it didn't really matter why the players had a map, just that it was a standard operating procedure. Like the maps the characters had in Dungeon Meshi, never really explained and never really questioned. So we just said "You have a map." And it worked! Huge quality of life improvement.