In design, re-roll mechanics sometimes get a bad rap. The thinking goes that if a game is designed well enough, they effectively become superfluous, and at worst, damaging. After all, if the players can re-roll the dice any time they like, why even bother rolling? There is a school of thought that says once the dice hit the table, there are no take-backs. The die is literally cast, come what may.
But here’s the thing. No game is perfect. Whenever you introduce variance, you will, inevitably, run up against edge cases. The master thief rolling a 1 and crashing through pots and pans. The famed warrior botching a roll and sending their weapon flying out of their hands. If these eventualities happen too often, the game becomes slapstick. But, argues the other side, if these things never happen, then the game becomes stale and boring.
What I think is missing from such a view is the prospect of player agency. When a player rolls the dice, they are, in effect, giving up some amount of agency. The GM, or the system, or some mixture of the two decides what happens next. If the result determined by the die is too incongruous with the vision the player had of their character, it can lead to disassociation and frustration with the game’s mechanics.
So, re-roll mechanics can clearly be a net positive on a game, but they can just as easily be a detriment. How do we ensure (or at least design for) the former and not the latter?
I often come back to FATE, but I do think it is the gold standard in terms of how it tackles re-roll mechanics. To re-roll a failed check in FATE, a player spends a “fate point” and invokes some Aspect of their character. Breaking it down, we can see there are two components to this mechanic: one, an expendable resource, and two, a narrative check on it’s use.
Let’s start with the latter. Depending on your style of GM and the playstyle of your group, the invocation of an Aspect can range in it’s permissiveness. Some GM’s will accept Fate points being spent if even a very esoteric or broad definition of the Aspect is invoked. Others are more restrictive, only allowing Fate points that fit within more narrow bands of Aspect interpretation.
This narrative check serves two purposes in it’s design. The first is that it keeps the game narratively congruous, by ensuring that players are competent only in the things that have flagged as their character being competent as. For example, the thief gets to re-roll a Stealth roll because they’re sneaky. They don’t get to re-roll the Strength check. This helps keep characters “in their lane” so to speak, and rewards players for thinking about their character’s strengths and weaknesses.
Secondly, the invocation of an Aspect forces the player to consider their character from an authorial standpoint. What is the intention of the Aspect written? Does it make sense for the character to be doing this? Oftentimes, these Aspect checks force the player to roleplay out their action a bit more, in order to justify the invocation. For example, if a player wants to invoke the Aspect “Sly as a Dog”, they have to roleplay their character taking their action so that it is in line with that Aspect.
Tying re-rolls to an expendable resource seems obvious, but it is important to consider why we do this. It is, essentially, a check on the previous “Aspect” check. If a player could argue for a re-roll whenever they did something in-character, it would bog the game down tremendously. Also, the expendable resource allows the designer to plan for (and math out) the probabilities around how many resources will be spent in a given session, how useful those resources will be, and how to scale the opposition appropriately in line with the player’s advantage.
Finally, re-roll mechanics direct the player to bear in mind what is important about the game. In Fate, re-rolls are tied to the Aspects, so players are encouraged to keep in mind what their Aspects are, and treat them as important part of play. In Fifth Edition DnD, Advantage (which, in some ways, is effectively a re-roll) comes from thinking carefully about the environment and a PC’s abilities, which indicates to the player that both the environment and ability management are key.
As I work on my own Blades in the Dark hack, I’ve chosen to key my re-roll mechanic off of the relationships between player characters. As in Fate, in order to re-roll a check, players must both expend a resource and narratively justify (in terms of the relationships they have to the other player characters) why that relationship might benefit them in this particular action. This, I hope, will focus the players on the relationships between PCs, and encourage them to develop, expand upon, and really dig into the interplay between their characters.