Image by Tim Ellis used under CC BY-NC 2.0

In the nearly half a century since Dungeons and Dragons first emerged from the primal war-gaming soup, game designers have gifted us with a plethora of different core dice mechanics. Most of them can be separated into two broad categories: static dice and dice pools. In static systems, players roll the same number of dice for each roll. This includes the ubiquitous d20 and the 2d6 of Apocalypse World. Meanwhile, dice pools have a variable number of dice, with the total number usually determined by the statistics being rolled. Players build a “pool” of dice based on their characters’ abilities.

Within dice pools, there are two further categories. In additive dice pools, players roll their dice, then add each die together for the total. I call the second category pass-fail dice pools,* and this is what we’re talking about today. In pass-fail pools, each die must come up a certain number or higher to be considered a pass, and PCs need a certain number of passes to succeed on a roll. Burning Wheel is a common example: PCs roll a number of d6 equal to their skill,* and each die that comes up a four or higher is a pass.

The pass-fail dice pool is my favorite type of core dice mechanic by a country mile. I think it’s the best option on the market, but I don’t expect you to just take my word for it. Let’s look at five advantages it brings to the table that put it above the competition.

1. Leveling Up Is Tactile

Everyone loves leveling up. There’s a very real satisfaction in seeing your character’s numbers increase and knowing that from now on you’ll be more capable than you were before. But in static-die systems, those new bonuses are only on paper. Sure, you get +5 with your axe now instead of +4, but the basic action of attacking is the same.

With dice pools, you feel your character leveling up in your hands. Instead of an abstract +1, you add an extra die to your pool. Playing a high-level character actually feels different than playing a low-level character. And when it comes time to roll the dice, you get the satisfaction of seeing your new bonus in action.

Leveling up isn’t the only way to feel your character’s capability changing. Tenra Bansho Zero gives PCs more and more dice as they go through anime-style power-up scenes or when they get wounded – heroes fight harder when they’ve been hurt! Rolling handfuls of dice immerses players in the game’s extreme action sequences, letting them feel like gods among mortals.

Some systems take this tactile advantage even further. Anima Prime has you move dice from one pool to another as the main component of combat. This creates important choices. Is it more important to have dice in your attack pool, or do you want to save some to power for your special abilities? While this could be replicated with numbers on paper, it won’t be nearly as satisfying.

2. Less Math Is Required

It’s time for you to attack your archnemesis. You take up your d20, add in your strength bonus, your base-attack bonus, your magic-weapon bonus, your terrain bonus, your dance-party bonus… Okay, I made one of those up, but you get the point. Many static systems require a lot of math before each roll. Additive dice pools are even worse. They ask you to add up a handful of dice after you’ve rolled, slowing down the game when you just want to know what happened.

With pass-fail pools, these problems will plague you no more. First, you don’t have to add up anything after the roll. Just count the number of dice that are over the pass threshold to see if it’s enough. Easy. And while it’s certainly possible for a pass-fail pool to have as many miscellaneous bonuses as a static system, they’re easier to add up. Instead of keeping the numbers in your head or marking them on paper, you put dice in your hand as you count. The physical reminder makes it much easier to keep everything straight. Once you roll, you don’t have to add the result to the number on your sheet; it’s right there for you to count.

Reducing dice math may not seem like much. For veteran players, it becomes second nature to add up all the damage of a fireball or the numerous bonuses for a diplomacy check. But even routine math can slow the game down, and an important roll is the worst time for that. Rolling the dice should be a moment of suspenseful excitement as you wait to see if your plans bear fruit, not a long pause in the game as you crunch numbers.

For new players, the benefit is even more pronounced. If you’re just joining the hobby, the math can be a major hurdle. Pass-fail pools reduce that burden and let you focus on learning the game.

3. Probability Is Easily Adjusted

For some groups, especially those that have been into roleplaying games for a long time, altering the probability curve for standard rolls can be a breath of fresh air. It changes how the game is played and opens new possibilities. Fortunately, pass-fail pools have the potential for such changes, if you want them.

Every system with a pass-fail pool has at least four sliders that can adjust the odds of success or failure on a roll. The first two are changing the number of passes needed for success and changing the number of dice a player rolls. Harder tasks mean more passes are needed, while dice bonuses and penalties are usually handed out based on a PC’s condition. If the character has an exceptionally sharp sword, that could be a bonus die. If the character is wounded, that could take away one die.

Many groups only need those two sliders, which is fine. But if you want to get creative, there are two others in easy reach. The third slider is the number each die needs to roll in order to be considered a pass. Changing that number has an unusual effect on the roll: it alters the odds of a successful roll but not the possible number of passes or fails a player could get.

Let’s say you’re rolling five d10s, and normally each die needs to be a six or up to be a pass. If that threshold is changed to five, then the odds of getting passes goes up, but the maximum number of passes is still five. If the threshold is raised to seven, it has the inverse effect. The odds of passes go down, but the maximum number is still five. This can be useful in situations where something makes a PC’s task easier or harder, but it doesn’t change their absolute potential. World of Darkness often uses it for magical effects, while Burning Wheel employs it for divine assistance.

Finally, the fourth slider is what number each die has to roll in order to “explode.” That’s a term meaning that you get to keep the original die, plus roll another one in addition to it. In most systems, this is the highest value on each die. Ten for d10s, six for d6s, etc. But there’s no reason it has to be those numbers. Lowering the explosion threshold makes for much more chaotic rolls, as the likelihood of chain explosions goes up. It’s not a great fit for every game, but if you want characters to have sudden bursts of ability, this slider is for you.

4. Randomness Is Kept in Check

Many static systems have an issue with too much randomness. Consider D&D. A character with 18 Strength is supposed to be at the peak of human ability, gaining +4 to strength-related roles. A character with 10 Strength is at the low end of average — the kind of strength you get from writing blog posts all day. It gives +0. In a contest of strength, both characters would roll 1d20 and add their bonus, giving the noodle-armed blogger a decent chance of besting the chiseled Adonis.

The same problem is rife across all kinds of rolls in D&D and other systems. When bonuses are too small, especially common at lower levels, the random dice roll has an oversized influence on success or failure. It feels like your character’s ability isn’t important, only subject to the fickle hand of fate.

Dice pools, pass-fail or otherwise, address this problem handily. Instead of adding your bonuses to a random roll, your character’s ability determines what the random roll will be. In a system like Burning Wheel, a character with 3 Power* would roll 3d6, while a character with 6 Power would roll 6d6. The chances of the champion weightlifter being bested by an office clerk feel more in line with reality under this model.

Another issue with randomness in static systems is the likeliness of fluke rolls. With a single die, be it d20 or otherwise, a minimum roll is as likely as a maximum roll. Even if your system doesn’t have rules for critical failure and success, that still means characters are just as likely to have a perfect moment or an absolute disaster as they are to get average results. That doesn’t match our understanding of how the world works, so it creates dissonance at the table. Some static systems use multiple dice, but that doesn’t usually solve the problem. Iron Kingdoms’ 2d6 is better than a single d20, but maximum and minimum rolls are still more heavily weighted than they should be.

Dice pools solve this problem by creating a bell curve. As you add more dice, an average roll becomes more and more likely, with maximum and minimum rolls becoming the least likely. When an uncommonly good or bad roll does happen in a dice-pool system, it feels like a special event and not part of a choppy reality simulator.

5. The Dice Always Matter

When a static system has random dice rolls that overshadow character ability, the most obvious solution is to increase character ability bonuses. This does help, but setting bonuses becomes a narrow balancing act. You see, if the ability bonuses get too high, it’s the dice that don’t matter. This is common in d20 systems, where bonuses can reach truly staggering levels, but it also happens in systems like Fate. In Fate, the bonuses gained from spending the system’s meta currency are far more valuable than anything the static dice can roll.

Rolling dice is a huge part of the enjoyment in playing RPGs. When the dice no longer matter, it’s just sad. There’s no excitement about the outcome of PC actions because those outcomes are never in doubt. When PCs have enough bonuses to always succeed, then there’s no satisfaction in victory. Worse, the dynamic can occasionally swing in the opposite direction, with difficulties so high that even good rolls can’t overcome them. That creates a sense of hopelessness.

It’s difficult to solve this problem in static systems, because bonuses need to start high enough that they matter in the rolls, but they don’t ever go high enough for the dice to stop mattering. If a static system has this careful balance at character creation, then dice will probably be unimportant to higher-level characters. On the other hand, if a system is balanced for higher-level play, then low-level characters will have measly bonuses.

Dice pools solve this problem the same way they keep randomness in check: bonuses aren’t in addition to the dice; bonuses give more dice. When a PC levels up in a dice-pool game, they don’t add a higher bonus to their roll; they add more dice. This difference may seem arbitrary from a statistical standpoint, but it’s very important. Rolling dice is fun. In a dice-pool system, what you roll is always important.

With all the advantages dice pools offer, they are well worth the cost of picking up a few extra d6s or d10s at the game store. This is especially true of pass-fail systems, which eliminate many of the dice pool’s downsides. Even if dice pools aren’t your favorite type of core mechanic, I hope you have a better understanding of the advantages they bring to the table.

Treat your friends to an evening of ritual murder – in a fictional RPG scenario, of course. Uncover your lost memories and escape a supernatural menace in our one-shot adventure, The Voyage.

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