Rules-Light vs. Rules-Sparse vs Rules-Simple

I want to draw a distinction between TTRPGs that are “Rules Light”, “Rules Sparse” and “Rules Simple”. By Rules Light I mean a very basic thing: the game, as in, the game book or the rules text, does not contain a lot of rules. By Rules Sparse, I mean a style of play: during play, rules are invoked infrequently. By Rules Simple, I mean: individual rules, regardless of their amount, are easy to apply. Let’s try some examples.

Rule Weight

I.e., the mere count of rules and mechanics in the game system or parts thereof, regardless of how often they may end up being used. Rule book page count is a first approximation.

Rules Light: 
The rules themselves fit on around 2 pages, maybe up to 10. There are perhaps one or two main resolution systems.
Into the Odd 1-pager, Roll for Shoes, Lasers & Feelings, Landshut Rules FKR, World of Dungeons.

In Between: 
The book may have 60 pages or so. There are at least two distinct subsystems.
D&D B/x. The Black Hack.

Rules Heavy: 
Hundreds of pages. Many subsystems.
AD&D2e, Shadowrun, The Dark Eye, FATAL.

Rule Density

I.e., how often mechanics are invoked during play; related to, although not the same as, Points of Contact, i.e., how much mechanics are required to establish something in the fiction. Note that rule density ultimately is not about game rules, but about game play; the same game/rule set can be played with different densities, so take the examples with a grain of salt.

Rules Sparse:
Very few Points of Contact. Mainly talking/”free roleplay”.
Social interactions in D&D B/x.

In Between: 
Dice come out at key points. Some rules structure what happens in between.
Dungeon World, Blades in the Dark. Traps and exploration in B/x.

Rules Dense: 
High Points of Contact. Nearly everything that happens is funnelled through the rules.
Combat on grids in D&D (any edition).

Rule Complexity

I.e., how cognitively demanding applying the rules is. How hard they are to learn.

Rules Simple: 
There are only one or two main resolution mechanisms. They require only one stage of mechanics, and there are no interlocking chains of rules calling on other rules.
Into the Odd.

In Between: 
There are a few subsystems with a few stages. There is a core set of mechanisms that are repeated ever so often. Rules call on other rules, but the funnels don’t get too long.
D&D B/x.

Rules Complex:
You need calculators and spreadsheets to do major things. 
Shadowrun, FATAL, The Dark Eye.

Observations

Now certainly these three aspects aren’t independent. Of course rules-heavy and rules-complex coincide. But let’s look at some exceptions that I find interesting; that is, what follows are various scattered notes for getting something out of these distinctions.

We can’t do a full 3x3x3 matrix, but we can do 3×3. It’s not possible to find 3x3x3 archetypal games that embody all possible permutations of the three categories because Rules Density is about play style, not the rule text. But we can at least do a 3×3 – or better just 2×2 matrix:

	Light	Heavy
Simple	Into the Odd (There is a one-page PDF with all the rules)	Electric Bastionland (Into the Odd plus 150 pages of random tables for world building)
Complex	Dogs in the Vineyard (It has one main resolution mechanism, but it’s a complex bidding contest plus raises and … Takes a while to explain as well as resolve.)	Shadowrun 2e (Multiple resource pools, both dice pool size and target number vary, stacked modifiers, … distributed over 100s of pages.)

Light games can be dense. If you play D&D B/x with minis on a grid and don’t get creative during fights, then for all its supposed lightness, it’s ultra dense: everything that happens in the game at that point is established by a rule. Players can in fact walk through an entire combat without ever leaving the domain of mechanics. You could even play Into the Odd combat that way, if everyone just sticks to trading damage. You could also play a fiction first/FKR game with a very high frequency of rolls.

Games can get heavier without getting more complex. Electric Bastionland has way more pages than Into the Odd, but it’s still just as Rules Simple and Rules Sparse as Into the Odd. The extra material is mostly just a trillion tables, and that’s 1. easy to use, 2. primarily matters during character creation (at least for the players).

Rules Density can greatly vary for players in the same game, in particular for GMs vs players. If for example the GM handles all rolls and rules, then play may appear to the players to be much less dense than to the GM, who will mentally wrestle all the mechanical complexity (although note that even when the players don’t know the rules, they will often intuit a difference between “GM fiat” and the GM following rules – or the GM pretending to follow, and secretly fudging, rolls and rules). Another example: in PbtA games, the GM might never roll, but constantly think of their principles and constantly conduct GM moves, while the players roll only very infrequently.

There can be trade-offs between weight, density and complexity. For example, Into the Odd doesn’t use (Dis)Advantage; instead, the GM presents entirely fictional consequences of difficulty and advantage, such as raised or lowered stakes. From a Rules Complexity perspective, this leads to simpler rules – a save is always a save – but it might make things harder for the GM, who cannot externalise difficulty, but has to keep track of things internally. Of course in an ideal situation everything follows from the fiction perfectly naturally, but I do want to point out that it can simplify the GM’s job if they can offload things to the rules.

The Myth of More Rules = More Options

While my default assumption is that where you want to settle on the three aspects is ultimately a matter of taste, I think that even though they would deny it, many writers and players fall prey to an obviously fallacious assumption: that a Rules Heavy game allows people to do more things with the game, and that making a game Rules Heavier leads to more options. For example, you can start attacking from horseback once you’ve bought the Mounted Combat Supplemental Rules. While certainly it can be hugely beneficial to play in the Penguin Kingdom when you’ve actually bought the Penguin Kingdom Sourcebook, in practice Rules Light games have a much broader spectrum of affordances. When you’re playing Rules Light, what you need for mounted combat is: 1. a horse, 2. that’s it, you only need a horse. In a game that implicitly suggests that only that for which you have rules can be attempted, then your options are limited to what’s between the covers of the game books. And there’s much more outside of them than inside. Of course, the game book won’t explicitly say that you can’t do what’s not described in there, but that’s how it plays out in practice more often than not.

For what it’s worth, my personal preference is: rules-light (I’m lazy and don’t want to read a lot of books), medium density (I like how dice allow introducing adversity and resolving uncertainty), rules-simple (lazy again). I think rules-complex and rules-heavy games are cumbersome to play and present a high barrier of entry, and I see little benefit to either. Rules density meanwhile I personally see as a more situational aspect.

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Notes: Rules-Lite is a surprisingly undertheorized concept. The great theoreticians at The Forge abstained from defining it, saying the concept is incoherent, preferring instead to talk first about Pervy vs. Vanilla and then Points of Contact. Well, I think the sheer amount of rules in a game, and the sheer amount of rules in game play, are not that difficult concepts to grasp, and are also rather descriptive of people’s preferences regarding which games they enjoy. So this was my attempt.

Thanks to Tom van Winkle for giving some feedback on a draft version of this! All remaining flaws are of course entirely my fault.