My Life As A Gamer: Macris Explains Good Game Master Practice

Over at The RPG Site, on October 25th, Alexander Macris wrote a fantastic post explaining the core of good Game Master practice for tabletop RPGs. I quote entirely here.

Anyone who has read my games know that I'm no fan of "mother-may-I" type mechanics. My game gives you rules for as much as I can think of. But 2,000 years of organized practice of law has found that there are no systems of adjudication that do not require a human adjudicator's involvement. The only argument is over how the adjudicator should be involved.

Start with precedent: A precedent is a legal ruling on a particular issue that can be used to help decide subsequent questions of law with similar issues. For instance, if a court is asked to decide whether a semiautomatic pistol is a legitimate weapon of self-defense, a previous ruling that revolvers were legitimate weapons of self-defense would be precedent. If the precedent is followed, it is called "binding." If the precedent is ignored, the new case is said to be "distinguished" from the old by certain new facts. For instance, the court might distinguish pistols from revolvers by pointing out that their ammunition capacity is much greater.

What does this have to do with role-playing games? One of the foundational role of the gamemaster is that of Judge, responsible for "ruling on grey areas not covered by the rules." The process of ruling on grey areas creates precedent - or what we call "house rules". How much precedent is going to matter will depend on whether your game is a "common law" or "civil law" game.

"Common law" originated in Old England as a history of legal rules created by judges when deciding disputes. The judges began with the traditional customs of how matters had been handled, and then over time built up a body of law based on those past precedents. Common law generally has little or no basis in anything written. The main disadvantage of a common law system is that there is no written "code" that citizens can consult to understand the laws of the land. The main advantage is its flexible capacity for growth and adaptation.

On the other hand, "civil law" originated in the Roman Empire as a collection or code of statutes created by legislatures. Judges interpret the statutes, but their rulings are not said to create law. The main disadvantage of a civil law system is that citizens can't depend on different judges to interpret the law the same way each time there's a case. The main advantage is that the laws tend to be more detailed and specific.

Faced with a question, a purely common-law court will look up what the court said last time it was confronted by a similar question. Meanwhile, a purely civil law court will look up what the most relevant statute says about the question and interpret it as it thinks best. Since each system has weaknesses, most legal systems today use a mix of both civil and common law, with legislators creating the overall framework of statutes, while judges fill in the gaps using common law methods based on precedent. Under this system, citizens can look at statutes to learn the baseline of the law, and then refer to past cases to understand how judges have previously ruled.

The analogy to a gamemaster in a tabletop game should, I hope, be clear. The game designer is the legislator; the game rules are the civil law; the citizens are the players; and the decisions of the gamemaster about grey areas in the rules are the common law.

A gamemaster running a rules-light game will end up acting mostly like a common law judge, forced to make rulings about particular situations without written statutes. In this case, precedent matters a lot. Fairness demands precedent. To prove this point, let's illustrate what happens when precedent is ignored. Imagine that you are running Basic Fantasy, a rules light game modeled after the classic 1980s editions of Basic Dungeons & Dragons. During a desperate retreat, Marcus, the party's fighter, wants to jump across a 15' chasm to safety. "Fighters jumping across chasms" is not covered by the rules. You decide that this is a test of heroic agility best resolved with an ability check against Dexterity. If Marcus rolls less than his Dexterity he will succeed; if not he will fail and plummet to his death. Marcus rolls a 9, less than his Dexterity of 12, and succeeds.

Next round, Quintus, the magic-user, decides he too wants to escape across the chasm. You again consult your rulebook and note that "magic-users jumping across chasms" is not covered by the rules. You decide that this is clearly a test of herculean strength, and demand an ability check against Strength. Quintus, with a Strength of 7, fails the roll, and his player demands to know why Marcus got to roll against Dexterity but he had to roll against Strength for the same task. What can you say to this criticism? That you're the GM, your word is law, and it's your right to rule however you like on situations not covered by the rules? That there is no written rule stating which attribute is to be used in resolving the success of jumps, so this is completely fair? You can certainly say that, but it's unlikely to persuade the player of poor dead Quintus.

Let's now imagine that a couple weeks have passed, and the party must now, once again, jump across this chasm. You once again check the rules and again see no game mechanic specifying the chances of success. You announce that each character has a 2 in 6 chance of falling in, but otherwise they jump across successfully. Morne, who has both 18 Dexterity and Strength, demands to know why he now has a 33% chance of falling in, and not the 10% chance he'd have if you stuck with either of your two past rulings. You shrug. "There's no rule that says it has to be an ability check," you say.

It should be obvious that this is not a healthy manner in which to run a game. A game run like this is a game that lacks fairness, common sense, and verisimilitude. Yet it's very common when playing a rules-light game to experience this sort of arbitrary decision-making on the part of the gamemaster out of an insistence that "there aren't really any rules!" This attitude derives from a failure to recognize that, just like a common law judge creates law when he decides a case, a gamemaster creates rules when he makes rulings. Fairness to the players demands that the rules for any given situation be the same for each player in that situation.

It's common to call games like OD&D, which heavily depend on the GM's judgment calls, rules-light games, in contrast to rules-heavy games like Pathfinder, which provide exhaustive mechanics. But with our deeper understanding of common law and civil law, we can see that a gamemaster's ruling is functionally a law, just like a game designer's rule is a law. Every rules-light game will over time become heavier with rules as its judge makes decisions about how things work. Rules-light and rules-heavy are only descriptive of the starting state of the game. The only question is how much the designer has left to the GM or the legislature has left to the judge.

This being the case, when you are running a long-term campaign, you should remember that every time you issue a ruling, you have added to the "common law" of the game design. You should write down your rulings, and apply them again to similar situations in the future - or distinguish them from prior rulings to explain why they aren't being applied. The very best gamemasters do this so consistently that over time that their long-running campaigns begin to develop an entire body of house rules covering the many special situations that have arisen in their campaign. Sometimes an entire new RPG develops.

That's how my own body of D&D jurisprudence, developed over hundreds of sessions of Classic D&D, ultimately became the Adventurer Conqueror King System. Of course, my efforts with ACKS are nothing compared to the old masters. After all, the entire corpus of Advanced Dungeons & Dragons is just Gary Gygax and crew's common law rulings on Original Dungeons & Dragons. Even more impressive, the legendary skill-based RPG Runequest began as a set of house-rules for D&D! (The transitional D&D-to-Runequest house rules were called the Perrin Conventions, named for Runequest's lead designer Steve Perrin.)

Not much more I can add. This is a bullseye on how it should be done, and why it needs to be done that way. You can't make the most of the liminality of the medium if you are as capricious and arbitrary as some Chaos God out of a Warhammer game (or the Elric novels that they are clearly derived from). If you need to write that down, then do it, but in any event notice that the key is consistency. Inputs have to match outputs reliably, just like we do in our real lives, or things break down real fast (ditto) and that's not a good thing for anyone (ditto).