April 17, 2015

How GMs Use RPG Books

It's been a busy week!  I have two half-finished full posts, but I figured I owed it to myself to put something up this week.

So today I'm going to talk about the approaches GMs use when we use an RPG's rulebook.  I've written a broad strokes post on this topic before, but it was limited to GNS theory; this post will focus on how a GM uses the rulebook.

If you're a game designer, keep up!  I'm talking about how your work affects us - your GMs.  I'm basically writing this to you.

Every GM uses each of these approaches sometimes.  Some GMs use some approaches more than others.  Some systems support some approaches more than others; and some even force GMs to use some approaches more than others.

Consider Dungeon World's principles and moves, for instance.  They explicitly require the GM to use the system in a particular way.  13th Age's lack of tables of modifiers prevents Detail Focused approaches to using the game book.  Vampire: the Masquerade supports the Learned Master approach to setting, while Fate supports the What do YOU think? approach.


  • Magical Tea Party:  The GM just decides what happens.  With a fair, empathetic, positive, collaborative GM, this can be fun.  Some GMs do this all the time -- but they have groups that love it.  Other GMs revert to MTP when your system bogs down, and the GM just tosses it out.
  • Off the Cuff:  The GM just takes a guess as to what to plan, and tries to stick close to what the rules say without getting bogged down.  Speed of resolution is more important than accuracy using your rules.  During the climax of a run, when a PC is thrown from a helicopter into the Puget Sound, a GM of Shadowrun 4th edition is not going to stop the action to open up the half-page of tables on swimming conditions and modifiers that those designers thought was appropriate.  She's just going to call for a roll with a penalty and move on, because the action is more important than some designer's insistence that all buoyancy factors be accounted for.
  • Detail Focused:  The opposite of off-the-cuff, these GMs not only use every single modifier you accounted for; they carefully consider and apply others to attempt to model the physics of the world the PCs are in.  If you're up on GNS theory, this is the GM with a "simulationist" creative agenda.
  • The Devil's Bargain:  I've posted on a game design blog about risk before.  A GM with a "gamist" creative agenda looks for devil's bargains in your system.  These are risk/reward tradeoffs presented as simple "multiple choice" questions.  Third edition D&D's weapon table was built out of devil's bargains:  "Do you use a sword with a 19-20 crit range and x2 damage on a critical or an axe with a 20 crit range and x3 damage on a critical?"  Such a GM -- or any GM in "gamist" mode -- will make table rulings using these options as well.  Despite its avowedly heavy Narrative focus, Fate gives PCs a Devil's Bargain at almost every opportunity - fight on or concede; spend a Fate point or take a Consequence; Create an Advantage or try to Overcome/Attack.
  • Drama or Bust:  In this mode, a GM will look at what's in your book, and if it does not raise the stakes, add excitement, or push the story forward, the GM will abandon it.  The GM might modify your rule or use it part-way it if it seems immediately obvious how to do so.  For instance, the Shadowrun situation, above could be resolved with "Drama or Bust":  The GM flips to the swimming rules, discovers a daunting table, sees the "choppy seas" penalty, and adds a dramatic detail - totally ignoring all the rest of the swimming modifier tables - "Good news:  you hit the water instead of the deck of the cargo ship passing by; bad news, you fall in the ship's tumultuous wake and are swamped under, make a roll at -4."
  • Story Solves System:  Sometimes GMs find that the system causes a problem.  Say your D&D PCs suffer total defeat at the hands of some goblins.  Instead of rolling up new characters, the GM can ignore the "death and dying" system without changing the rules by saying that the goblins staunch their wounds and drag them to captivity, where they awake several hours later, tied up in a cave.  In Cyberpunk 2020, a Netrunner would go hack a computer system, leaving the rest of the players with nothing to do for at least a half hour.  A story solution was to have a NPC who did all that for every run -- either an ally of the PCs, a competent hireling, or an NPC assigned by the PCs' employer.
  • System Solves Story:  Sometimes GMs have no idea where to go next, so they turn to your rulebook, looking for a mechanic to give the game direction.  D&D has random monster tables; Night's Black Agents has the Vampyramid; etc.  Sometimes the GM just uses the regular system to generate some excitement.  In Pathfinder, the GM might say "well, you guys are carrying a lot of gems and gold in a bad area of town; make a Perception check..."  The key here is using the system to generate the seed of the next story moment, then growing that seed into an interesting event that ties into the ongoing narrative.  In the Pathfinder example, the PCs spot a pickpocket making off with some of their gems.  The pickpocket will lead them to the thieves' guild and the next plot clue either by fleeing, if they're captured and interrogated, or if they're treated kindly.


The setting that comes with an RPG runs the gamut from none to too much.  What counts as too little or too much depends on the GM.  And GM styles in using setting vary between GMs, between games with the same GM, and even moment-to-moment in a session.

Some games come without any setting at all (GURPS).  Others come with only a vague hint of an intended genre (Fate).  Others come with a strong genre focus (D&D); others come with a complete and detailed setting (Ars Magica); some use the real world, with additional overlaid setting details (Call of Cthulhu); and some come with a heavily fleshed out setting atlas and gazetteer (Forgotten Realms, Vampire: the Masquerade).  
  • Genre Only:  No matter what the book provides, the GM adheres only to the genre assumptions, throwing out any published "facts" that get in their way.  For instance, an Eberron GM might invent an entire nation, or ignore the existence of Kalashtar and Dal Quor; but stick to the fantasy-punk high-flying adventure genre.
  • Seed Facts:  The GM might look for interesting inspiration in the setting provided, but once they find inspiration, they go where their imagination takes them, ignoring your published work.  For instance, a Vampire: the Masqureade GM might learn about the Sabbat Vaulderie, but totally ignore the entirety of the Sabbat, instead using this practice as something neonate coteries do in the Camarilla to drive a story with a strong theme of generational change and resistance from the older generation.
  • Learned Master:  Some GMs revel in learning more about the setting than the players, and being the expert.  Some players love it when their GM does this, so that their experience in the game feels like discovering a rich and detailed world.  This was one of the selling points of the old World of Darkness; and also a limiting factor.  The best WoD storytellers were the ones who could pull this off; but it took quite a lot of investment.  When they revised their game lines, they largely removed this "metaplot" and published supplements with different and contradictory takes on the same core settings to try to encourage more of the "seed facts" setting approach from their GMs, which has a lower barrier to entry.
  • Reference Library:  The GM uses the setting like the Learned Master, but without the mastery.  The GM looks setting facts up if there's time, or delays long enough to find time.  This is common with modern-day real-world games.  If the PCs want to find a biker bar in New Jersey, the GM can google "biker bar in new jersey."  Wikipedia and Google earth are the best game supplements you can have for a modern day game.  But what about a fictional world?  Games set in the Star Wars universe can access Wookiepedia, and there are similar sites for popular published game systems from Vampire and to just about every D&D campaign world.  And there are low-tech solutions, too: GMs often find themselves flipping through campaign setting manuals and sourcebooks.  Designers!  It's important to have a good index for your sourcebook, whether that's a solid print index or a hyperlinked table of contents in a PDF.
  • What do YOU Think?  Story games and RPGs that give the players a lot of agency encourage the GM to let the players add setting details.  Some GMs who've experienced these games carry this technique over to more traditional RPGs with a lot of success.  You may find a Pathfinder GM answering a player's question this way.  "I listen at the door - what do I hear?"  "There are four orc warriors in there.  What do you suppose they sound like?"  Or even "I don't know -- what do you think would be cool?"  In this mode, the GM is expecting the players to use as much of the provided setting detail as they want.  The GM usually rejects any suggestions that are too far out of genre for the scenario.

What do you think, readers?  Is there some way GMs use RPG books that I haven't mentioned?  

Postscript:  I've seen GMs use rulebooks as improvised weapons, decoupage, art books, and doorstops.  Have you seen GMs using their rulebooks for hilarious or unusual purposes?