Violently and Mercilessly Killing Your Children

Except, y’know, not like your offspring, but like your ideas.

So, in the second part of this series of blogs, I came to the conclusion that the current dice system for my tabletop RPG Blackmarked is hot garbage. It’s terribly non-evocative, the actual probability distribution was all wrong, and it had a lot of seemingly arbitrary math tacked on.

Unfortunately, I had already written about 50 pages of rules using this system. It was deeply ingrained into all of the other systems. What do I do? Do I just try and fix it up a bit so I don’t have to change too much? Maybe at least try to develop a system for which the Target Numbers end up looking similar?

No. Of course I don’t.

Just because it’s going to be a lot of work doesn’t mean it shouldn’t be done. Like I said, a core dice mechanic is essential to a good game, and will permeate through all of its parts. To leave something so fundamentally uninteresting at the core of my game would be dooming it to a death sentence.

So what’s a better system? Well, basically, the only way to find out is the same way you generate any good design: raw iteration. Create a new idea, put it through the grinder, keep what works, trash what doesn’t, repeat until game is good. Anyone who thinks they have the best version of their design in the first iteration is either divinity given flesh, or an idiot.

So, here I am, stuck thinking up a new system. I needed something interesting, something that captured the mood and theme of my game at its first level. Eventually, what I came to was going back to one of the games that inspired BlackmarkedDark Souls. Specifically, what I thought of was how every action in that game ties back to the Stamina system, which limits how much you can do in a single span of time by forcing your character to rest. Alright, I thought, here’s a system I can work with. A bit of reworking, and…

Idea #1: the dStamina System

  • Every dice roll is a 2d6 roll (two, six-sided die) plus the relevant Skill. If the result is greater than or equal to the Target Number, it’s successful.
  • Every character has a pool of extra d6s called the Stamina Pool, which may be added on to any roll. Resting is the only way to replenish this pool, and depleting it causes exhaustion.

OK, so immediately we have a simpler system, and one which seems to invoke the theme of characters slogging through this world, instead of marching triumphantly, a little better. There’s a pretty glaring problem, though, which ruins this system. Basically, if Target Numbers are low enough, or Stamina pools high enough, players will just save their pools for one big dice roll at the end of a session, throw all but one Stamina die in the roll, and make success almost mathematically guaranteed. People aren’t going to want to spend this pool on anything but the biggest rolls, and those rolls are going to be rendered trivial as a result. More often than not, this system is just going to be 2d6 + Skill, with no alterations, which is boring.

Idea #2: the dStamina System Mk. II

  • Every dice roll is a (2+Skill)d6 roll. If the result is greater than or equal to the Target Number, it’s successful.
  • The Stamina Pool exists as per Mk. I

OK, so here’s a small iteration, designed to try and keep the core structure, but lessen the player’s ability to auto-win important rolls by removing their guaranteed skill modifier, and replace that with a more random way of factoring in Skills, by having Skills add extra dice. Unfortunately, for all but the most obscenely large Target Numbers, creating a dice pool of about five dice or more will pretty much guarantee success, with every additional die only marginally increasing your odds.

This is for a Target Number of 12. See how success is almost assured once you hit a dice pool of 5 (3 dice added)?

For this system to work, either Target Numbers need to be so high that performing no or low-Skilled checks need to be literally impossible, or Stamina Pools need to be so small that they’ll basically never get used. Both are not good.

Idea #3: the “Try Again” System

  • Every dice roll is a 2d6 roll plus the relevant Skill. If the result is greater than or equal to the Target Number, it’s successful.
  • If you fail, you may incur one Strain to reroll your 2d6, this time as 2d10. If that fails, you may do so again to reroll your 2d10 as 2d12.
  • Strain causes negative effects to your character, and must be rested away.

Alright, so if incurring exhaustion to add dice to your dice pool seems pretty broken, how about using exhaustion to make the dice in your pool better? This system removes a player’s ability to just burn away their character’s stamina to ensure success, which is very good, while still offering a good motivation to use up that stamina (rerolls).

The problem I have with this system is that it causes some weird interactions with the Skill system. Spending 2 Strain increases your average roll result by 6, which means that if Skill numbers are low, the benefit of having high Skills is not going to be equivalent to the gain of just burning 2 Strain, and specialist characters are going to be less useful. If Skill numbers are high, however, Target Numbers are going to have to be high to match, and all of a sudden that +6 on average from Strain rerolls are going to be borderline useless. We’re so close, though.

Idea #4: The Strain System

  • Every Skill a character has is represented by a size of die, four-sided all the way to twelve-sided. Every dice roll is just rolling the die of the associated Skill. If the result is greater than or equal to the Target Number, it’s successful.
  • You may roll a larger die than your Skill allows, but doing so risk incurring Strain (more so for larger jumps in Skill).
  • If you incur too much Strain (from pushing dice rolls, or from taking damage), the size of every single one of your Skill dice starts to go down.
  • Strain can only be regained by getting a good night’s rest.

If Skills and the die size system are interacting weirdly, we can solve that by just making them one and the same. This system has a variety of benefits. One, it makes the Skill system as a whole much clearer, and makes it more obvious how much better one Skill rank is than another (someone with d4 Strength will only match a TN of 4 a quarter of the time, while someone with d6 Strength will match it half of the time).

On top of this, boosting the size of your die is still just as good as before, and can allow you to perform some feats outside of your normal skill set in really heroic ways, but the cost of doing so is enormous: you run the risk of making your entire character less effective for the entire rest of the in-game day. Again, boosting die size to perform feats beyond your Skills doesn’t render Skills irrelevant, because your Skill is your die size. These seems pretty in-theme to me: being a big, courageous hero up against impossible odds is exhausting. Hell, just getting through the day will probably be exhausting, which, if you’re an adventurer for-hire, it should be.

Narratively, this system also has the benefit of emphasizing downtime. As a character adventures, they’re naturally going to incur a decent chunk of Strain one way or another, and unless the party wants to go on completely gimped, they’re going to need to think about how they’re guaranteeing themselves a good night’s rest, which is an interesting thing to have to think about. This means that Game Masters can do some really interesting stuff with a party’s downtime, and emotional distress can have a real, significant effect on a party (by ruining their good night’s sleep), and can have a significant effect on the game. All of a sudden, the throwaway line of “We set up camp and go to sleep” becomes a lot more interesting.

On top of this, this system can form the base for other interesting systems to be built on top of it. For example, since deciding upon this system, I built another attribute for characters, their Vice. Basically, getting a good night’s sleep is easier (and thus, getting rid of Strain is easier) if a character indulges their Vice beforehand, which can be anything from getting really drunk to gambling to indulging their bloodlust to just shutting themselves off from the others and reading forbidden knowledge.

For example, the original Witcher game, Geralt’s vice is pretending that Dice Poker involves any skill whatsoever and isn’t just fantasy Yahtzee.

Now, characters have a mechanical incentive to be the kind of bad people that match the setting, and now they have a built in character trait that makes developing a character’s personality easier, and Game Masters have a way to introduce interesting situations into that character downtime (the guy you just lost all your money to in a card game offers you an odd job to win it back, the guy you’ve been drinking with all night is actually the target you’ve been chasing for the last 2 weeks, etc.).

This is the power of iteration. By just making system after system, thinking about each and making meaningful changes, I’ve gone from a weird, non-evocative, arbitrary dice mechanic to one that’s extremely evocative of my setting. This system probably has its own flaws, and will still need iteration, but by not being married to my original ideas, I’ve gone from something OK to something great, and my game will only improve as a result.


How To Make Good Games By Ruthlessly Cheating At Statistics

The most impressive thing to me here is that this guy wrote all of this backwards.

So, I’ve discussed the sweeping idea of what a good central dice mechanic is, now I’m gonna do a more in-depth analysis on my other tabletop game project, Blackmarked, to see exactly how I go about reviewing these mechanics.

So, quick refresher: Blackmarked is a tabletop roleplaying game about cutthroats and killers trying to survive in a low-fantasy world of war, religious turmoil, plague, and the occasional undead sorcerer. This game is supposed to be vicious: characters die fast, combats are quick and dirty, and the best way to survive is usually to not fight. Nobody’s a hero, everything sucks, and possibly the only divine force in the world is a god of chaos who just wants to burn everything to the ground.

Cool, what’s the dice mechanic? Unfortunately, to my own admissions, what I have right now is pretty boring. Check it out:

  1. For a player attempting a check, they take 3d6, add a number of d6s equal to their relevant Skill, then add/subtract dice equal to the modifier, and roll ’em.
  2. Every die that comes up a 4, 5, or 6 is a success.
  3. Get a number of successes equal to the Difficulty Number + 1 to pass the check.

I don’t like this system for a number of reasons. First of all, it’s not terribly evocative of the game’s mood or, in fact, much of anything. On top of that, it’s full of details that seem initially arbitrary. Why do you get an initial dice pool of 3? Why the plus one to the difficulty number?

Despite all of this, I thought in my mind that these rules should create a sort of probability curve like I wanted: one where victories were not uncommon, but still had to be fought for. After all, the dice should come up a 4, 5 or 6 about half the time, so for a Difficulty Number of 2, you should succeed about half the time with no additional skills.

Here’s the trick of game design, though: don’t just trust your gut. Some people might be pained to hear this, but sometimes you’re better off applying some good ol’ fashioned math to your game to see exactly how things tick in the systems you’ve made. And with this wisdom in mind, I set off to determine the probabilistic equations I would need to determine the approximate likelihood of success in this system given Skill, modifiers, and Difficulty Number.

But, like, on the other hand, statistics is hard. There’s a bunch of numbers and stuff you have to work with, and generating an equation which outputs the number I want can get unwieldy when your dice mechanics get more complex, and you have to recalculate for every variable….

But wait! There’s a solution! There are two kinds of probability in statistics: theoretical probability, which is generated through math, and experimental probability, which is generated by just doing the thing a bunch of times and recording how many times the event you’re measuring for happens. I don’t have to crunch the numbers, I can just roll these dice a bunch of times and keep track of how many times I succeed.

And by “I”, I mean a computer can. I’m a programmer after all.

The Hacker
Hell yeah, cyberspace!

With that in mind, I modified this dice roller program in Python I had lying around to suit my needs. Basically, it just rolls according to my skill check rules above for every likely combination of Skill rating, modifier, and Difficulty Number, and tells me how many times that roll succeeded. So I whipped this up, told it to test every combination of variables a million times, and went to dinner, and let it chug.

When I came back, I found some interesting experimental results. Check out the output file.

The first thing I looked at was what I would consider baseline rolls. That is, a character of Skill level X attempting a challenge of Difficulty Number X with no modifiers. Let’s see how those numbers came out:

  • Skill 0, DN 0: 84.49% successful
  • Skill 1, DN 1: 68.82% successful
  • Skill 2, DN 2: 50.03% successful
  • Skill 3, DN 3: 34.35% successful
  • Skill 4, DN 4: 22.63% successful
  • Skill 5, DN 5: 14.51% successful

Whoa! No! These experimental probabilities seem to imply that really hard tasks are basically impossible, even if you have the very high skills , which doesn’t feel right to me. I’m all for punishing rolls, but I think a high-skill character should succeed at a hard thing more than fifteen percent of the time.

Furthermore, this curve feels weird from a narrative sense. An idiot can do an idiot task almost all of the time, while a genius can only do a genius thing a sliver of the time? So you’re incentivized to play an unskilled character and do unskilled things? Eew.

Let’s take another measurement. Let’s see how probable every Skill level is to succeed at a task of DN 2 (which I considered average), with no modifier:

  • Skill 0: 12.47% successful
  • Skill 1: 31.33% successful
  • Skill 2: 50.03% successful
  • Skill 3: 65.57% successful
  • Skill 4: 77.32% successful
  • Skill 5: 85.55% successful

Ok, so here’s the thing about these rolls. To even stand a 50/50 chance of succeeding at this average task, you have to have at least a Skill of 2, or else there’s little statistical probability you’ll succeed. Considering this is a system where failure usually leads to painful death, I don’t know that an RPG meant for long-term campaigns will be viable with these probabilities.

Moreover, think of how limited the GM’s design space for obstacles becomes. If he throws anything at their players of a DN greater than 2, unless that’s the thing which the player has specifically built their character to deal with (skill points are kinda sparse), they’re probably going to fail, meaning there are 3 viable Difficulty Numbers that will keep your party from immediately failing at everything they do, and a very small space in which to present foes. All of these quirks combined, plus how much I didn’t like the system to begin with, means I need to toss the whole damn thing out and start over.

Also of note is the fact that this doesn’t mean this system is inherently “wrong” or bad, it’s just not what I’m looking for. I don’t want a system this prone to failures, if I’m going to have failure in combat almost always lead to player maiming. I’m going to need something a bit more player-friendly. If you were designing a game in which the consequences for failure were lesser (maybe even a comedy game centered on failure), or just a game where the players are supposed to frequently get killed, this could be totally viable. It’s just not expressive for what I want. I’ll figure out a system that does that in the finale of this three-part blog.


What Is A TRPG? A Miserable Little Pile of Dice Rolls!

I am never not a sucker for some fancy, specially designed, nice dice (these specifically can be bought from Dark Elf Dice)

I’ve been on a big tabletop RPG kick recently, partially do to discovering a variety of interesting indie TRPGs, partially due to discovering a few excellent TRPG podcasts and YouTube channels, and mostly due to my personal gaming group meeting with far greater consistency than before. Whatever the reason, this surge in interest has led to a resulting surge in tabletop RPG design.

Specifically, I’m working on two games. The first, Blackmarked, I’ve written about before on this blog. As a quick refresher, it’s a quick and brutal low-fantasy game that’s equal parts Dark Souls and Dishonored. The second game is a newer project of mine called Asphyxia. This game is set in a far-flung sci-fi future, and centers on a party of special agents who get sent in by corporations to perform missions in a quarantined colony.

In my mind, the single most important part of any tabletop RPG is the central dice mechanic. This mechanic will be spun and remixed several ways within the rules to fit certain contexts (skill checks with no ranks in the skill, contested checks, etc.), but this dice mechanic will basically play a part in every mechanic of the game.

Despite this, people don’t give as much thought towards these central dice mechanics as they should. Many people, whose experience with tabletop RPG experience doesn’t extend much further past D&D, assume there’s basically one mode: roll some dice, add some of your numbers to it, and see if the result is bigger than the bad number. There’s nothing wrong with this, but it’s hardly the end-all of mechanics. In fact, looking at this mechanic shows how tailor-made it is for D&D specifically.

Think of it this way: D&D specifically has players roll a twenty-sided die, add their positive modifiers to it, and try to beat some target number. The thing about a d20 is that, as far as dice go, its results have an extremely wide range. There are twenty possible results, and each of them has equal probability of coming up. This works well with the central motifs of D&D: you’re supposed to play big, dumb heroes, and to tell epic stories, you want epic victory and miserable defeat to be relatively common occurrences. Given that rolling a 1 is automatic failure, and rolling a 20 is automatic success, this dice system ensures that even the most epic and ridiculous feats are always at least 5% possible.

What if we didn’t want a game full of epic successes and dismal failures? What if we’re making more of a post-apocalyptic game, or a survival game, and we want our players to barely succeed, to have to fight and struggle for every minor victory. A simple way to do this is to change one thing: instead of rolling 1d20 for skill checks, roll 2d10, or two ten-sided dice.

Is that the same? Nope! When you have multiple dice and add them together, a bell curve tends to form around the middle value of the possible sums. Despite the fact that 2d10 still has basically the same range as 1d20 (2-20 vs. 1-20), there’s only one way to roll a 10 on 1d20 (rolling a 10), but there are tons of ways to roll a 10 on 2d10 (1 and 9, 2 and 8, 3 and 7, 4 and 6, 5 and 5, 6 and 4, and so on). Meanwhile, there remains only one way to roll a 20 (rolling two 10s). Thus, those middle results become more common. Set your average difficulty numbers right around the middle of that bell curve, and you’ll find players frequently barely succeeding.

(This post on Glimm’s Workshop details this point extremely nicely.)

“You roll an 11. By a margin of one, you don’t die of cholera!” “…dope.”

Let’s talk about one of my games. In Asphyxia, I want to capture the feeling of a tactical operation slowly going badly as it goes on and complications arise. I want players to start a mission feeling like kings of the world, and have this world basically beat them down until they drag the shells of their former selves back home, clutching onto anything they still have. I could have used a simple d20 roll-higher system like D&D, but that doesn’t really capture that sense of increasing peril, does it? There had to be something more interesting.

In fact, there is, and as it turns out, I found a way to capture the mood I want in something as soulless as the dice mechanics. Here they are, in simplified form:

  1. When characters want to do something, they take 2d10s and roll them. If either comes up lower than their Target Number (set by their ranks in any relevant skills), they succeed.
  2. Assorted bad things in-game (wounds, damage to equipment, and stress, primarily) will add Disadvantage Dice, which are d6s, to these rolls.
  3. If, in a dice roll, any Disadvantage Dice come up as the lowest result of a roll, no matter how good the d10s came up, the check is automatically failed.

I purposefully designed this system with a few nuances in mind. Players are going to receive constant visual reminders of exactly how bad things are going, as they add more and more of these bad dice to their rolls as the session goes on. Disadvantage Dice are powerful, as they average lower as d6s than the d10s the players normally roll. However, d10s have a 0 as the lowest result, while d6s only have a 1, meaning no matter how bad things are going, players always have at least a slight chance to squeeze out a victory.

This is what I mean when I say that core dice mechanics are the most important part of a tabletop role-playing game. By designing this central dice mechanic in a way that emphasizes my core theme, I ensure this theme will seep in to every part of the game which involves this core dice mechanic, which will be basically every part of the game.

If you take the leap into the world of tabletop RPG design (I highly recommend it, it’s one of the most interesting sandboxes as far as the design space goes), think about your dice mechanics. Read some RPGs with “weird” dice mechanics. Think about different configurations of dice that you could roll, different ways to interpret their result, and think about how those configurations and interpretations could be designed to suit your game.