Sixteen: The Core Mechanic is Born

If you came to the blog today looking for part one of the Fire Emblem Fates Character Guide, I apologize. Due to some trips I have scheduled around Mother’s Day, I have a limited writing schedule. Because I only have the time to invest in one big post this week, I chose to invest that time in Friday’s fanfic. When I get back from travelling I will buckle down and get to work on the guide. Thank you for your patience, and I hope you’ll stick around for today’s post!


While I don’t have much of anything on paper yet, Sixteen has been growing a lot in the past week or so. I’ve been spending a lot of time in my car driving, and that gives me a lot of time to brainstorm ideas and to work out how I want this RPG to work. A couple of posts back, I mentioned that I wanted Sixteen’s core mechanic to be based around the number 16. Today, I thought I would talk a little bit about the inspiration behind that and how I intend to make it work.

So naturally, I chose the number 16 because there are sixteen personality types in Myers-Briggs. That is pretty straightforward. When I decided to use that number as a major thematic element throughout the design of the game, I thought it might be cool if I could figure out a way for 16 to be the only difficulty class (DC) in the entire game. If you aren’t familiar with the concept of a DC, it’s a term used in D&D (and probably in other tabletops as well) to represent what number you have to roll on the dice to succeed. Higher DCs represent tasks that are harder to accomplish, while lower ones represent easy tasks.

There were some other ideas that paired with this concept of a single DC. Along with only having one number as the goal number for the game, I wanted to have a system that only uses one type of dice: the d20. This is something I really love from Mutants and Masterminds. You don’t have to worry about buying a set of special RPG dice that come in a specific combination, or loading up on fifty six-sided dice because every player needs anywhere from eight to a dozen. All you need is a d20, something that can be bought pretty cheap and that each individual player can carry to the table like their signature weapon.

In addition to that, there’s an aspect of Dungeon World that I really wanted to keep in regards to dice: the fact that the GM never rolls any. The book describes this as every player taking their fate into their own hands. As the gamemaster, it takes away the temptation to fudge a roll here or there, because you don’t roll. Period. Only the players roll, so they only have themselves to blame – or congratulate – when the dice hit the table.

So here I was with three main ideas. 1 – The only difficulty class for the whole game should be 16. 2 – The only dice necessary should be one d20. 3 – The GM should not have to roll any dice. How in the world would I combine these together into one core mechanic for the game?

I started off by thinking about the d20 itself. Say I don’t add any other dice or numbers to it. I’ve got a d20 and I need to roll at least a 16. That means I succeed on 16, 17, 18, 19, and 20, five out of twenty, or one quarter. 25% chance of success, 75% chance of failure, statistically speaking. Those aren’t particularly great odds. So what would I need to add to have better odds? Well, a modifier of +5 would put me to 50/50, and a +10 to 75/25 in favor of success rather than failure. Looking at it this way, having 16 as the DC of every single check suddenly seems more feasible. If a check is supposed to be pretty easy, it should have a modifier of +10 or higher. For something kind of easy, put it between +7 and +10. For something kind of challenging, it’s a little more or less than 50/50 between +6 and +4. The check would be difficult but not impossible between +0 and +4. Once the modifiers start getting negative, it is statistically improbable – almost impossible – to succeed. So for 16 to be the only DC in the game, the modifiers to the dice rolls will be the controlling factor in how difficult things are for the characters.

That’s fine and dandy, but let’s look at this long-term. The characters will get stronger as the players play more and more. That means those modifiers will be going up, and the ability to beat 16 is just going to keep getting easier and easier. With such a low DC, how will the game remain challenging even at later points when the characters are more powerful? The answer to that lies in the villain design, and here is where I discovered how the GM would never have to roll dice.

From a stat perspective, enemies will simply be a collection of modifiers. These modifiers are subtracted from those of the players when rolling. Say we have a sharpshooter whose Measure stat (read: accuracy) is 10. A d20 + 10 means that this guy is going to succeed in hitting his target 75% of the time. Now say he’s shooting at a quick villain with a 5 in her ability to avoid. That 5 is subtracted from the sharpshooter’s 10 in Measure, and suddenly the chances of success drop from 75% to 50% – that roll is going to be a lot trickier and more interesting now. It’ll work the same way for dodging enemy attacks. Say we’re playing as a noble sorceress who is attacked by a black knight. If our Avoid is 6, but the knight’s attack is 5, that brings our modifier own to a measly 1. That’s only a 30% chance of success…things are looking pretty bad for us, but there’s still hope to pull through. Because enemy stats simply modify player stats when rolling the dice, even when attacking, the GM never has to roll anything and the players can control their own fate.

So there’s the core mechanic of Sixteen in a nutshell. Roll a d20, add your score in an appropriate stat and subtract the enemy’s, and if you beat 16 you succeed. It’s a pretty simple mechanic that won’t require a lot of sifting through a book to look up specific rules. It can be pretty easily accomplished with just the info on the character sheets, and that’s something I definitely believe in – less time in a rulebook and more time at the table having fun.

Things are coming along pretty nicely with Sixteen, and I am excited to continue working on the project. It may be a bit longer before my next post on the subject; as I mentioned at the beginning of this post, I have a lot going on in the next few days. On top of that, designing the jobs based on the sixteen Myers-Briggs types will be pretty extensive. But it won’t be long before I’m ready to talk about that as well. In the meantime, I hope you are excited for the progress being made and looking forward to the opportunity to enjoy a game of Sixteen!

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