I've probably should've started with this post, on some level. The dice rolling mechanics are usually one of the first things mentioned about any RPG in its back, from my experience.
Well, better late than never.
I'll start off with what I hear relatively frequently - rolling dice is meant for interesting actions. To define an interesting action: any action in which failure will produce a result with consequences for the characters. For the matter, let us take a door. Many things can be done with a door, but only certain things warrant a roll. If it is locked and between the characters and something they want, a roll would make sense. If there's nothing that the characters would actively want on the other side, no roll and probably no lock are needed. In another instance, the door is unlocked but there someone on the other side who wants to open it and it swings to his direction. If the characters wish to avoid allowing him to open the door, they're gonna want to grab that door handle and quick. This would definitely warrant a roll, since the order of who gets to the handle first is important.
Short and simple, as I opened with: if failure has consequences, a roll would make sense.
The second thing to address is additional attempts after a failure. The characters are assumed ambitious yet competent, and with that competence comes a certain awareness of when you fail and why. With that assumption in mind, a character that has failed a roll has no reason to believe that any additional attempts at his current skill level will yield different results. So, a failed roll cannot be reattempted by that same character until he has gained a rank in the relevant skill.
In Stuff of Legends, the only dice that are used are six-sided ones, henceforth d6(s). It is recommended that you have an amount of d6s in the double digits at the table, and at least 4 per player, including the judge. It is recommended that you have 3-4 green dice and 3-4 red dice, as they serve as advantage and disadvantage dice.
The advantage dice are added to the ones the player would normally roll and after the roll the player removes dice until he is left with the amount he would have rolled with the advantage dice. This allows a greater freedom in results and increases chances for doubles or more by a large percentage.
The disadvantage dice are similar to advantage dice, but are different in one way: instead of removing any dice they choose, the player instead removes the lowest dice until he is left with his normal amount. This doesn't guarantee an increased failure chance, but it takes a lot of freedom from the player.
There are 3 types of rolls in Stuff of Legends, corresponding to different situations: skill rolls, reaction rolls and contests.
The basic type of roll the players will make is a skill roll. They take their own skill rank and match it against the skill opposition. If their own rank is above the opposition, they have some flexibility in the amount of dice they roll. If their own rank is under the opposition, they must roll as many dice as the opposition.
Example: an archer aims her bow at a monster. The archer's Ranged skill is at rank 3 and the monster's Reflexes and Acrobatics are both at rank 2. The archer may choose to roll as few as 2 dice or as many as 3. In another case, a different monster has Reflexes and Acrobatics at rank 4, forcing the archer to roll 4 dice, despite only having a rank 3 Ranged Skill.
In many cases, after an opposing party has made a skill roll, a reaction roll may be done. Reaction rolls are used when defending, for instance. After a skill roll was successful, the judge will usually ask if the target of the skill roll is interested in reacting. When reacting, the skill roll result acts as a type of minimum threshold: the reacting party tries to roll under their own threshold, but above the opposing skill roll result.
If the skill roll result is above the reacting party's threshold, no reaction can be made.
Example: the archer from before has hit her target with the rank 2 skills. The monster, attempting to avoid the arrow, reacts with its Acrobatics. The archer's Ranged result was 12 and the monster's Threshold is 15. If the monster hopes to avoid the arrow, it can't roll less than 13 or more than 15. Had the archer hit with a result of 16, the monster would have had no hope of avoiding the attack.
Contests are relatively short rolling contests between two parties, each aiming for a certain goal before the other. Normally, the goal is the same, like racing to the end of the street, climbing the cliff face first or reaching for a certain door handle before someone else.
In contests, the rolls are made differently than in skill and reaction rolls. First and foremost, contests have a predefined length, measured in victories, and predefined round ending conditions, measured in margin of loss. Both are predefined in advance of each contest by the judge.
The length, or victories, is how many times one party needs to win against the other. Winning can be achieved in two ways - either your succeed in a contest round and the other party does not or the other party's margin of loss is too big. A length of 1 or 2 is common, while 3 or more are exceptional.
The margin of loss is how many success ties can be had. If both parties succeed, the one with the lower result takes a disadvantage on their next roll. The margin of loss is how many disadvantages may be taken before the round is over. If the round is over by having too many disadvantages, the other party wins. A margin of loss of 1 is very common, 2 relatively common and 3 or more extremely rare.
A contest with a length of 1 and a margin of loss of 1 is called a quick contest. All other contests are simply contests.
I believe that these 3 mechanics cover every type of action that might come up - active, reactive and opposing.
As normal, critiques and comments are welcomed.