Blades in the Dark uses six-sided dice. You roll several at once and read the single highest result.

• If the highest die is a 6, it's a full success—things go well. If you roll more than one 6, it's a critical success—you gain some additional advantage.
• If the highest die is a 4 or 5, that's a partial success—you do what you were trying to do, but there are consequences: trouble, harm, reduced effect, etc.
• If the highest die is 1-3, it's a bad outcome. Things go poorly. You probably don't achieve your goal and you suffer complications, too.

If you ever need to roll but you have zero (or negative) dice, roll two dice and take the single lowest result. You can't roll a critical when you have zero dice.

All the dice systems in the game are expressions of this basic format. When you're first learning the game, you can always "collapse" back down to a simple roll to judge how things go. Look up the exact rule later when you have time.

To create a dice pool for a roll, you'll use a trait (like your Finesse or your Prowess or your crew's Tier) and take dice equal to its rating. You'll usually end up with one to four dice. Even one die is pretty good in this game—a 50% chance of success. The most common traits you'll use are the action ratings of the player characters. A player might roll dice for their Skirmish action rating when they fight an enemy, for example.

There are four types of rolls that you'll use most often in the game:

• Action roll. When a PC attempts an action that's dangerous or troublesome, you make an action roll to find out how it goes. Action rolls and their effects and consequences drive most of the game.
• Downtime roll. When the PCs are at their leisure after a job, they can perform downtime activities in relative safety. You make downtime rolls to see how much they get done.
• Fortune roll. The GM can make a fortune roll to disclaim decision making and leave something up to chance. How loyal is an NPC? How much does the plague spread? How much evidence is burned before the constables kick in the door?
• Resistance roll. A player can make a resistance roll when their character suffers a consequence they don't like. The roll tells us how much stress their character suffers to reduce the severity of a consequence. When you resist that "Broken Leg" harm, you take some stress and now it's only a "Sprained Ankle" instead.