Core Mechanic

The core mechanic in a TTRPG is the main die roll used to for task resolution. Here's how SGS's core mechanic works. It looks complicated, but that's because we're including all the possible options in it, and because we're defining individual phases that would be readily apparent in the middle of play. Most rolls won't be this complicated, especially when you get used to what parts you can ignore until you want to use them.

Basically, this page is huge because we're going super-saiyan nerd-mode on the minutia. 🧠


  1. Pick Skill, Stat, Equipment, & Action being used
  2. GM determines outcome type & DN or target
  3. Roll the dice, determine success, & figure attack margin or outcome
  4. Add margin to damage/effect and compare with target's thresholds
  5. Apply effects for thresholds exceeded

Action Diagrams

To illustrate the two main cases, let's first look at a couple of diagrams. These show a high-level view that might be helpful for understanding the total structure for people who are visual learners.

Diagram Legend

graph TD c((Person or
Character)) n[Number] t[[Table
or Chart]] d(Dice) f{Decision} p>Process] e{{Endpoint}}

Overcome Action

flowchart TD pc((Player
Character)) k[Skill] t[Stat] e[Equipment] gm((Game
Master)) l[[The Ladder]] dn{Difficulty
Number} ot{Outcome
Type} dr(Die) ar>Overcome Roll] c{Comparison} o{{Outcome}} pc --> k k --> t pc --> e pc --> dr t -.-> ar k -.-> ar e -.-> ar dr --> ar gm --> l gm --> ot l ---> dn ar --> c dn --> c c --> o l --> o ot --> o

Attack Action

flowchart TD ac((Attacking
Character)) dc((Defending
Character)) ak[Skill] at[Stat] ae[Equipment] ad(Die) dk[Skill] dt[Stat] de[Equipment] dd(Die) dh[[Thresholds]] ar>Attack Roll] dr>Defense Roll] c{Comparison} th{Threshold
Comparison} po{{Reduce
Pool}} m{{Miss}} hit["Hit
(A-D)+weapon damage"] ac --> at ac --> ak ac --> ae ac --> ad at -.-> ar ak -.-> ar ae -.-> ar ad --> ar dc --> dt dc --> dk dc --> de dc --> dd dc --> dh dt -.-> dr dk -.-> dr de -.-> dr dd --> dr ar ----> c dr --> c c -->|A < D| m c -->|A >= D| hit hit -->|damage| th dh --> th th -->|wounds| po

Task Definition

First, define the task. The task is defined with these parameters:


Pick which skill the task relates to. This might be selected by the player from the beginning ("I want to use Arcane to Attack!"), it might be asked for by the GM ("Haha yeah please roll a dodge for me.") or it might be decided by consensus ("What skill is slithering between the bars?").

It's possible that the PC doesn't have the required skill. In that case, the default is skipping adding any skill value to the roll.


The vast majority of the time, the stat of the roll is determined by the skill, but sometimes the GM may request a skill roll to use a stat the skill isn't tagged with.

If the PC doesn't have the stat, again, just skip it and add everything else to the roll.


Sometimes the character wants to just perform an action, other times the character wants to use a specific piece of equipment to perform an action. This is the difference between trying to climb a wall with Athletics versus trying to hit someone with a Longsword.

When the character is using an item, that item's skill value (if it has the skill in question) is added to the roll. If not, the default is to add no extra equipment skill value to the roll.

Action Type

The type of action should be apparent from what the character is trying to do. Trying to hurt someone is an Attack action. Blocking, dodging, or otherwise evading harm is as Defense action. Use Overcome actions to get past obstacles or perform difficult challenges. Use the Create Advantage action to give yourself a bonus, put an aspect into play, or set up another action. The Initiative action is used to determine who goes first in complicated or time-sensitive situations.

There's no generalized default here, just use the action that makes the most sense.

Action Types are discussed here in more detail.

Outcome Type

There are three possible outcome types. The default is Success, or binary outcome. Either you succeed or you fail. There are also Quality outcomes, where you're checking to see how good a roll is, not just whether it suceeds or fails. There are also Time outcomes, where you need to know how fast someone can get something done.

The GM decides the outcome type.

It's possible for the GM to switch from the default Binary outcome type to Quality in the middle of the roll process for some kinds of tasks, particularly information gathering.

Outcome Types are discussed here in more detail.


The last part is for the difficulty. The GM decides the difficulty of unopposed rolls. The opposition determines the difficulty of opposed rolls by rolling themselves. Their roll becomes the difficulty.

The GM doesn't need to specify a difficulty for Quality or Time outcomes, because they'll be compared with a ladder of values. The GM can also keep the difficulty of Success outcomes hidden for suspense or story purposes, if they choose.

Again, most of the time, figuring this out will be a split-second decision. SGS does a lot of work to make as much of this setup instantaneous.

Rolling the Dice

Once the task is somewhat defined, the player of the character rolls their dice. In the SGS System, the size of die that is rolled for checks depends on the game being run. Some games might use 1d20 to emulate D&D, while others might use smaller dice to adjust the importance of luck vs skill.

Once the dice are rolled, the roll and its modifers are added up.

Token Modifiers

While the player is counting up their roll, they can decide that they want to spend some tokens to increase the roll. The tokens are spent and the roll is modified as dictated here.

Compare Roll

Next the roll is reported to the GM, who compares the roll with the difficulty or ladder, depending on the Outcome Type.

Success Outcome

If the roll exceeds the difficulty, it is a success. if the roll is equal to the difficulty, it's a tie. If it fails to exceed or equal the difficulty, it's a failure.

Quality & Time Outcome

The roll is compared with the game's Ladder. The ladder is a table that has values in one column and descriptive elements in the other. The GM bases their narration on what level the character's roll exceeds.

Calculate Effect

Some rolls are complete after determining success, like bluffing or researching. Other rolls have contingent effects. The most obvious of these is damage inflicted in combat. Contingent effects are the province of Success Outcome type rolls, because they depend on how well the attacker's roll does against a defense value.

All contingent effects are calculated the same way.

Subtract the difficulty of the roll from the roll total. This is the margin. If the item or user has an effect value, such as Damage, that value is added to the margin. The effect value can be a single number, a number of dice, or both. Roll the dice and add the bonus, then add that to the margin. This is the total effect.

The purpose of adding the margin to the roll is to represent how characters who are really strong or accurate do more damage with the same weapon than those who are weak or clumsy. This is similar to adding a strength or dexterity bonus to weapon damage in D&D.

Compare With Thresholds

The total effect isn't given directly to the target as damage like in D&D. Instead, the value is compared with the target's Thresholds. Match the type of damage to the type of threshold, then figure out what the highest threshold the damage exceeds is.

Generally speaking, there will be two tracks of thresholds, with 3 levels each. For each level exceeded, the target takes 1 damage.

Check Off Pools

Next, simply check off that number of boxes. From that point forward, the target takes an autobound penalty to their rolls equal to the number of boxes they have checked off.

This penalty has several effects. It makes the combat feel more violent and dangerous, it make players really consider their actions, and it models how characters are not as good at fighting when they're hurt. Characters can temporarily ignore the effects of their wounds (running on adrenaline) by spending tokens.