View Full Version : Which is better? 2d6 or 3d6 based systems?

2014-12-13, 05:12 AM
I'm making a detective themed role-playing game at the moment and my original idea was to use 3d6 for skill checks. However, after a few playtests I realised that this makes it much more likely for players to get numbers in the middle of the spectrum, with only a 1 in 216 chance of getting an 18. However, I only want to use d6s for simplicity's sake. So I was wondering, would it be better for me to just use 2d6 for skill checks instead.
In summary, what are the advantages and disadvantages of 2d6 or 3d6 based systems?
Thanks for any help you can give me.

Freelance GM
2014-12-14, 02:49 PM
2d6 has less complexity, but you can do some fun stuff with 3d6- like what happens if 2 dice are the same.

Here's a helpful link with some relevant math.

Don't forget to consider the way things like rolling doubles (or possibly triples) can possibly alter the results.

Also remember that abilities that allow re-rolling one or more dice can dramatically alter the probability of success, too.

Exploring other mechanics like this can make the game more involved, and also give you more room to create cool abilities.

2014-12-14, 03:02 PM
2d6 has been a classic since the day dice were first invented a half dozen Millennia ago. Also, they come up as 7 on average, and as everyone knows; 7 is objectively one of the best numbers.

Seriously though, die type super, SUPER, does not matter. It may very well be among the least significant decisions you'll need to make.

At most its an aesthetic choice. Exalted for example works well with a dice pool because when you build up a mighty pool these's a satisfying tactile demonstration of the mighty scale of your numbers. Percentile works for Warhammer because it has a harsh and ridged sort of feel, telling you just exactly how bad your odds are.

Pick whatever you like the feel of and move on.

2014-12-14, 03:36 PM
I agree with Freelance GM that the best option is 3d6 with added rules to make use of doubles and similar. To me, 2d6 has not got enough variation, and works better with a system that uses smaller numbers (which maybe your system does). But you're also right that 3d6 is a bit dull by themselves, becuase they do not give extremes.

I know that you did not ask for a new system, only pros and cons about the two options, but i came up with an idea that i think might be good.

If you use 3d6, but with an added rule where if two of the dice are 6's, the third one is doubled, and if two of the dice are 1's, it is only the third die that counts. So, if you roll 6, 6 and 4, the result would be 20, and if you roll 1, 1 and 3, the result would simply be 3. This would increase the extremes, particularly the high rolls, with the highest roll being 24 (at the same odds as 18 in your system) and the lowest roll being 1. It would also be easy to add special rules to this system where you, in one particular skill, get to double the third die when you get a double of 5's, not just sixes, or whatever.

This might not suit your system of course, and i havent thought about it all that much, maybe the odds still arent working, but it is an example of the kind of rule that i think would make a 3d6 system good. Althought of course, what Doomhat said is also true, the number of dice is not the most important thing.