Hi there! I'm going to be writing a bunch of devlogs about everything in 36th Way, in pretty much the order I developed it. This one's about the most basic mechanics of 36th Way: rolls, Advantage, and Disadvantage.

Why 3d6?

13th Age uses a 1d20 in a fairly typical way for most things: roll it, add your level and maybe 1 or 2 other things, see if it's bigger than something else. I've never liked the d20 in any game. So when I started this project it was the first thing to go. 3d6 has the same average as 1d20 (10.5) so it seemed like a logical choice - and especially because at the time I thought I was just going to change the die, a few mechanics, and the starting 4 classes and keep everything else the same. That didn't last, obviously.

As a foundation, 3d6 has a nice bell curve. It even works pretty cleanly with 13th Age's Natural 6+/11+/16+ mechanics: if you swap in 9+/11+/13+, you get the same 25%/50%/75% proc rate. But as you'll notice by those tightened values, 50% of rolls are going to fall in that 9-12 range. This will provide a much more even result. And you can gather that each +1 in that range is equivalent to about 12-13%, which means that if most of the numbers you're trying to hit land in that range, things like escalation are about 2.5x as powerful as they are with a d20. This means the pacing feels a little better and the spare +1 you get here and there feels more meaningful. (It also means the math needs tightening up in general, but that's not worth diving in too deep yet.) Crits and crit fails are less frequent - I set the former at Natural 17+ (~2.3%) and the latter at Natural 3 (~0.5%) - but we'll get back to that in a bit because it's not that simple when you bring in Advantage and Disadvantage.

Advantage and Disadvantage

Let's talk about those now. Regarding those spare +1's, I wanted to get rid of them for the most part - at least the in-combat ones. Re-calculating added values sucks and someone's bound to do the math wrong, forget something, or take awhile sorting it out. I liked the idea of Advantage and Disadvantage - that is, roll a d20 twice and take the highest one or lowest one - but I always felt it wasn't granular enough. But, we're using 3d6 and not 1d20! So we can do something like that but more granular.

So I did. If you gain a number of Advantage, you roll that many extra dice and take the highest 3 (or the 3 of your choice if you're fancy). Likewise, if you gain a number of Disadvantage, you roll that many extra dice and take the lowest 3. The advantage (haha) to this works on a few levels. For one, you don't have to recalculate anything, just roll more dice and take the good or bad ones. It's pretty fast, especially with a dice roller like roll20 that can do it for you! And comparing to d20 Advantage, you can stack a few up, which allows for different values of granularity, as I'd noted earlier. You can have up to 3 either way (so you end up with "roll twice as much, take the highest/lowest half").

A second observation is that it ties in well with Natural X+/X- mechanics. The breakpoints for most of those are 9+ and 13+, and 1 Advantage/Disadvantage puts the average of a 3d6 roll at about 13 and 9, respectively. This means that Natural 13+ effects will happen at a 50% rate instead of a 25% rate with 1 Advantage, and Natural 9+ effects will happen will happen at a 50% rate instead of a 75% rate with 1 Disadvantage. So not only does it add to your roll, it changes those frequencies! Speaking of frequencies, the final observation is that it changes crit chance. Giving your allies Advantage makes them crit way more - about 2x, 5x, and 9x respectively. And it's an even steeper reduction for Disadvantage. All of this means that support is a crucial role!

Next time!

So that's the absolute basics for resolution. Watch out for my next post, in which I'll talk about the basic building blocks of a character - no attributes, no race, all killer, no filler. Until next time!