The entire StoryTeller system is based on one single concept of dice rolling. Rather than rolling one dice and trying to get above a number, you roll a quantity of dice determined by some method against a difficulty determined by how difficult the task is. The number of dice that roll higher than that difficulty give you the number of successes that you roll. The number of successes that you achieve determine how well you did whatever.

Sounds complicated - its not.

For instance: if you have 4 dice, and attempt a difficulty 6 task, you roll those 4 dice against difficulty 6.

If you roll:

2 2 3 4, then you have rolled 0 successes
2 3 4 6, then you have rolled 1 success.
7 8 9 0, then you have rolled 4 successes.

Balancing this however, is the fact that ones cancel successes.

So if you roll

1 2 4 6, then you have rolled no successes, because the 1 cancels the 6.
1 4 6 7, then have rolled one success, the 1 cancels the 7.

In addition, if you roll more ones than successes, then you have botched. This means that you have not only not suceeded in the task, but have stuffed it up very badly somehow. If you are making a sandwich, a botch would be something like accidentally putting vinegar on the bread instead of butter.

Characters doing stuff.

Normally when characters want to do something, the number of dice that they have to accomplish a task is determined by an Attribute+Ability pair. For instance, running after someone, you might pair together Dexterity and Athletics. Noticing that someone is lying to you might require a Perception and Subterfuge roll.

Eg: If Tom wants to convince Bill that he has indeed paid the Telecom bill, then Tom's player would check to see what ratings Tom has in both the Manipulation attribute and the Subterfuge ability. If Tom has a Manipulation rating of 2 and a Subterfuge rating of 3, this means Tom's player can roll 5 dice to try and lie.

The difficulty of any task is usually set by the GM. An average difficulty is 6, a hard task might have a difficulty of 8, while an easy one might be 4.

Eg: The GM decides that Bill normally trusts Tom, so the difficulty is only 4. Tom's player rolls his 5 dice\dots

If Tom's player rolls 3 4 5 6 0, Tom has 4 successes and blithely assures Bill of the payment of the Telecom bill.
If Tom's player rolls 1 2 3 4 5, Tom has 1 success, and thinks for a second, the tells Bill "Thats right, I paid it this morning."
If Tom's player rolls 2 3 2 3 2, Tom has 0 success - a fail, and Bill doesn't believe him at all.
If Tom's player rolls 1 1 2 1 4, Tom has botched - Bill points out that the unpaid Telecom bill is in fact attached to the fridge behind Tom, and starts yelling at Tom for lying to him.

Some examples of rolls

To pick a lock: Dexterity and Security
To try and understand what someone really feels: Charisma and Empathy
To see how your horse is holding up to a long trip: Perception and Ride
To understand a difficult passage in a legal document: Intelligence and Law
To jump off a second floor safely: Dexterity and Athletics
To scare someone off: Appearance and Intimidation
To try and hit someone with a sword: Dexterity and Melee
To parry a blow: Dexterity and Melee
To dodge a blow: Dexterity and Dodge
To create an item of art: Intelligence and Expression
To spot a pickpocket in a crowd: Perception and Citywise

Some rolls don't behave the same way. Damage rolls, once you have hit someone, usually require a player to roll their character's Strength, plus some number of dice. Soak rolls, to avoid getting hurt once you have been hit, need a Stamina roll. Clerical magic needs a straight Faith roll, whilst magic casting just rolls your Spellcasting. As with other rolls, you have a rating, which is the number of dice you roll, against a difficulty, that the gm determines (and sometimes tells you).

Complications

Willpower
Before making a roll, you can opt to spend Willpower on the roll. This means that you can expend temporary Willpower points to ensure automatic successes.

Eg: Tom wants to translate an ancient manuscript. Tom's player decides that it is fairly important to get it right, and spends a point of Willpower. Tom has a rating of 4 in Intelligence and 2 in Linguistics, so his player rolls 6 dice. The difficulty is 8, because the language is so weird. Tom's player rolls 1 4 8 9 2 5 5. Normally, this would mean Tom got 1 success, but with the Willpower expenditure, it becomes 2 successes.

The only roll that Willpower cannot be spent on is a Willpower roll. All expenditures of Willpower must be declared before the roll.

Luck
Once a roll has been made, you can also opt to spend temporary luck points to cancel any ones.

eg: Milya wants to jump a chasm, about 10 feet across. Her player rolls Milya's Dexterity and Athletics (2 + 1) and rolls 1 8 1. Normally this would mean a botch, and Milya would probably plunge down the chasm to die. Milya's player decides this is non-optimal and decides to spend a luck point to nullify one of the 1's. So Milya ends up with a fail, and barely makes the leap, twisting her ankle as she does so.

Combat

Combat progresses as follows:

All protagonists roll for initiative. Wits + Melee roll, difficulty 4
eg: Tom rolls his Wits + Alertness dice (5 dice) and rolls 1 3 5 8 6. He therefore gets 2 successes. Milya rolls her Wits + Alertness dice (3 dice) and gets 7 9 6. She therefore gets 3 sucesses.
Counting from the highest number of successes down to zero, each combatant resolves their action.
Combatants using weapons roll either Dexterity + Melee or Dexterity + Missile Weapon, against the difficulty for their weapon. Brawling combatants roll Dexterity + Brawl to see if they connect.
If a combatant connects, they then roll the number of dice appropriate for damage, difficulty 6. Reroll any 10s that are rolled.
Once damage has been declared, the victim rolls their Stamina dice to try and soak the damage, difficulty 6. Reroll any 10s
eg: Milya's action was to try and spit a goblin with her sword. She rolls Dexterity + Melee (4 dice) and gets 3 7 5 8. Her sabre has a difficulty of 6, therefore she gets two successes. She connects.
Now her player rolls the damage for a sabre. Milya has a Strength of 2. A sabre does Strength + 4 dice of damage. Therefore Milya rolls 6 dice. She rolls 10 4 1 7 8 6, and then re-rolls the 10 which comes up as a 4, so 3 successes. The goblin rolls its Stamina (1 dice) and rolls a 4, failing. The goblin therefore takes 3 full Wound Levels of damage.

Alternatives.
Dodging:
A character with dice left in their dice pool can declare a dodge at any time (even if they rolled 1 on their initiative and their attacker is moving on 3). Characters that have their action before an attacker can opt to save their move up to make a dodge instead of attacking.

Characters who wish to physically dodge roll Dexterity + Dodge
Characters who want to parry roll Dexterity + Melee

eg: Tom strikes out at an orc, rolling his Dexterity + Melee. He rolls 2 successes. The orc decides that maybe it doesn't want to attack Tom, but dodge instead. It rolls its Dexterity + Dodge dice and gets 3 successes. As the orc got equal or more successes than Tom, it dodges.

Other Details

Spells
Spells take one time tick per level to cast. They are begun in the tick in which the character starts to resolve their action.

For example, Tom wants to cast Magic Missile. He rolls 2 successes on his Wits + Alertness roll, so he goes on 2. On 2, Tom starts his spell. It is a level one spell, so it comes off in 1 tick. On 1, Tom rolls his Spellcasting dice to determine the effect of the spell.

Spells always come off before people who botched their initiatives can do anything. A spell that has not been finished by tick 0 comes off then.

Eg: Bill wants to cast a Cure Disease spell. He too rolls 2 successes for initiative, and starts casting his spell on 2. Normally the spell would be finished 3 ticks later, but this would be below 0, so instead it is finished on 0. On 0, Bill rolls his Faith rating to determine the effect of the spell.

Armour
Armour is useful stuff. It makes it harder to do damage to you. But it has the disadvantage that it becomes harder to move in armour as well. In general, the more protection armor offers, the harder it is to move.

For example, wearing leather armour offerts an extra dice to soak with. So if you are hit, you would roll Stamina + 1 dice to soak the damage. Leather is not too confining, so there is no real loss to agility.

On the other hand, plate mail offers an extra 5 dice to soak with. When you have damage inflicted upon you, you have your Stamina plus 5 more dice to roll to cancel damage successes. Conversely, your dexterity is reduced by 4.

If your dexterity is reduced to below 0 - you can't move. You just don't have the natural togetherness to wear this degree of confining armour.

NB Armour only works against biffing damage. It provides no extra defence to fire, lightning, magic, etc. Some enchanted armours may provide this kind of defence.