RPG Rule Mechanics: Universal Versus Varied

Role-Playing game rule systems fall into two categories: universal and varied. Universal games use a single mechanic for every action. “Alpha Omega” uses the same skill check system for everything from picking locks to shooting a pistol. Varied systems like some older “Dungeons and Dragons” versions use percentile for picking locks and a d20 mechanic for combat. The ultimate example of a varied system is “Aces and Eights.” It is a series of mini-games that bear no resemblance to each other. A bar fight uses poker chips in a bidding system to determine success and a mounted chase uses a deck of cards.

Clearly a universal system is easier to learn, since only one mechanic resolves all contests. Conversely, the varied systems offer greater complexity, but some players enjoy the variety. I am curious as to how my readership feels about this issue. Should a role-playing  game use a single mechanic to resolve all actions or use different mechanics for different aspects of the game?

Trask, The Last Tyromancer



Trask is a long-time gamer, world traveler and history buff. He hopes that his scribblings will both inform and advance gaming as a hobby.

One thought on “RPG Rule Mechanics: Universal Versus Varied

  • November 17, 2009 at 2:13 pm

    I think it’s a matter of picking the best tool for the job, and picking a mechanic that reflects the overall feel of the game.

    A resolution mechanic is just a way of generating a value along a certain numeric distribution that has certain statistical percentages associated with every value. How you present that is up to you, but in the end, math is math. A d20 is just a percentile system broken up into 5% chunks. A d100+value vs. target number system is just a percentile system in reverse. a 2d6 or 3d6 or 2d10 mechanic is just a bell curve along a 1% to 100% statistical distribution, but all the possible values can be placed along the line.

    Ultimately, it’s all a matter of personal preference. If I use a 1d20-roll under mechanic for ability checks but percentile dice for Thief skills, but my thief skills are all broken down into 5% blocks, mechanically there is absolutely no difference.

    Now, granted, I think there might be an argument for having more than one resolution mechanic for things that are not necessarily character-based resolutions. For example, you might have a d100+value vs. target number system as your main mechanic, but still like the idea that for initiative, you just have everyone roll a d10 and highest goes first. Or just have a sliding 1d6 chance of something happening while on the road while traveling.

    I guess what it comes down to is, resolution mechanics are all, in the end, representations of probability. Determine how you want to represent probability of success in your game, and go with it. If you feel that not all probability mechanics should be linear, then use a bell curve. If you think having “mini-games” best fits the feel of your RPG, then go for it. As long as it all makes sense, doesn’t feel arbitrary, and is clearly explained with appropriate examples, you should be good to go.

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