Rationales for Mechanics (or the Case for Designer Notes)
Why do rpgs use mechanics? Such a simple question, but one with such complex answers. It seems obvious that those answers would be key in the design process or in the judging of an existing game. After all, it's only by way of knowing your needs that you can chart the nature and placement of mechanical systems properly in such a way that the game meets the desired goals.
Sadly it seems very common for rpg designers of the current day (especially in the free or small print world) to skip right by that question. It is painfully common for me to receive what is in effect a blank stare upon quizzing a game designer as to the reasons and rationales behind their design. Typically the only response is "I was looking for something different" and "It does what I wanted it to do", without being able to express what was different, or what it is doing. The end result is I receive in answer a jumble of words typically tossed on the back cover of a book as basic marketing ("Powerful yet simple mechanics!", "Yes it's a floor wax and a desert topping!").
With this as the common response, there is little reason to wonder that mechanics in many games seem almost pointless- seemly existing often just because other games have included them. The result is typically a distraction from (or misinterpretation of) the purpose of the game, reducing what could have been a powerful design to yet another rpg that will sit on the shelf.
Let's take a moment to consider some important and common rationales, just so we're on the same page. I don't think these are by any means the only reasons, but they are at the very least reasons every designer should consider his mechanics in the light of.
I. Limiting Player Options
If any single rationale could claim to hold prominence in game design, it would be this one. Why can't my 1st level Age of Heroes fighter kill an ancient red dragon with his penknife? Because the combat rules make that all but impossible as a core requirement of design.
The natural result of any mechanic is to limit options. What those options are limited to however determines the actual rationale for the mechanic. In this specific case, the reason is to prevent specific player actions and choices because they are unsuited to the intended purpose of the game.
Advancement rules are typically guided by this rationale. The player gets X amount of power within the game for Y amount of effort, not no effort at all. Requiring a certain Strength level to break down a specific door is yet another example while falling damage is yet another (for those games limiting a character's ability to jump off 40 foot walls to reach a battle).
II. Providing Meaningful Player Choices
The classic example here is combat mechanics (a subject I've already spent some time on in my previous Elements of Tactics article). The idea is to present a complex and diverse enough set of choices in order to make the decisions of the player important in determining the outcome of the game events.
III. Inspiring Player Action
Examples of these are the Sanity rules from Call of Cthulhu which provide a nudge of when and what type of insanity the player is struck with, but leave the exact details of expressing it up to the player and GM.
Psychological and Drama mechanics are normally created with this rationale in mind, to respectively inspire role-play and story creation.
IV. Replacing Player Choice
These mechanics are intended to flat out replace decisions by a player or GM.
Single roll combat resolutions are typically this type of mechanic, the idea is to remove any tactical choices beyond that of the decision to engage in battle (and sometimes even that isn't offered). Another example is the use of straight up 'social' skills like 'bribe' and the like. The concept is to remove choices and actions from extensive play that are felt to be either beyond the ability of the players or outside the focus of the game.
Another way of looking at these mechanics is as a simple and quick method to resolve something so that the game can go forward. Removing significant player input is perhaps the fasted way to achieve that goal.
V. Provide an Illusion
Some mechanics exist to aid in suspension of disbelief. Thus a game may include detailed currency rules because the players have a hard time believing that everyone in the world uses the same coins.
Some mechanics provide an illusion of Rationale II above. A typical example is providing a wide range of combat maneuvers that suggest a good selection- but upon using some math it's revealed that a single one of the provided maneuvers is always the best choice. Sometimes this is a result of failed design, at other times it's done on purpose (often using dice pools mechanics in order to make the illusion more difficult to pierce).
There are other possible reasons of course. I'm sure you can add a few with a little bit of thought.
Once one knows the rationale for a mechanic, it becomes much easier to determine the Layer of Design it applies to as well as its form. Rationale IV mechanics for example tend to be simpler than Rationale II systems by nature.
There's just one gotcha to keep in mind. A little thing called the 'the eye of the beholder'.
Remember Rationale III above, a little thing about inspiring player action? Most of the time I see such mechanics I'm not inspired. Instead I see a Rationale IV mechanic- something that takes my choices away in order to meet a goal of the game design (in the case of Call of Cthulhu, it's enforcing the genre concept that everyone goes insane- a type of railroading with respect to the role-playing of a PC).
Here's another example- Rationale II mechanics become little more than Rationale V mechanics if the players can't grasp the actual effects of choices in the system (dice pools tend to cause this effect by making probability determination exceedingly difficult).
Take a few mechanics from a favorite game of your own and try fitting them into each of the above rationales. With a little bit of work and a talent for seeing things though the eyes of others- you may be surprised how many rationales a single mechanic can fit in.
So in the end you may design a wonderful game, one that has developed mechanics that fit their reasons for use at every point. But in the end the final result may be viewed by others in a completely different light than what you intended.
But all is not lost. The solution to this sad state of affairs is right in the subtitle to this article.
Write them. Spend as much time and effort on them as you did in the design of your game- for they determined the design of your game. Put them directly in the book or on your website. Explain why you selected the mechanics you did, what they do in your game, why you rejected other possibilities.
You'll achieve four important outcomes.
First, you'll produce a better game. One tailored to your needs and perfect for the type of play you desired.
Second, you'll provide the best guide there is to how the game was meant to be played. And you'll do it in a way far better than the typical stilted 'example of play' fiction.
Third, you'll define for the reader the terms on which your work is to be judged, so that in that judging they are not looking for a game you never designed. It is much better to hear "Even if I don't care for the style, Game X does what it intends almost perfectly" instead of "This games sucks".
And fourth, I won't get a blank stare when I ask you what makes your game different or what you were trying to achieve. For not only will you be able to answer that question, you've already written it for me meaning the only thing I'll bother you about is the details of your vision. And isn't the details of the designer's vision the reason for making a game in the first place?