Dice and Uncertainty

Purpose

This document defines how uncertainty is resolved within the Tactical Dice Game System.

It establishes:

• What dice exist in TDGS
• What each die is allowed to represent
• How success and failure are determined
• How extreme outcomes are identified
• When dice are used and when they are not

This document does not define character capability, progression, skills, damage, or narrative interpretation. Those concerns are addressed in later documents.

The goal of this document is to ensure that all uncertainty in TDGS is resolved consistently, transparently, and in a way that remains readable by humans and deterministic for computers.

Dice Taxonomy and Roles

Tetrahex the ObscureD4

"Each die has a job. Know your roles, know your dice."

Meet Tetrahex the Obscure →

Dice in TDGS are not interchangeable. Each die has a defined role. A die may only be used for the purposes listed here unless a later rule explicitly expands its use.

Resolution versus Magnitude

Nyxara TidelightD12

"First we ask 'did it happen?' Then we ask 'how much?' Never both at once."

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TDGS draws a strict boundary between:

• Whether something happens
• How much happens

Resolution determines success, failure, avoidance, or opposition.

Magnitude determines quantity, damage, duration, area, or scale.

Resolution and magnitude are always resolved separately, even if they occur as part of the same action.

Resolution Rolls

A resolution roll is any roll whose primary purpose is to determine whether an action succeeds or fails.

Resolution rolls:

• Use a d20 by default
• May be opposed or unopposed
• Resolve independently of magnitude

A resolution roll produces one of four outcomes:

Resolution rolls never determine magnitude.

Critical Success and Critical Failure

Sir CritsalotD20

"A natural 20 isn't luck—it's destiny announcing itself. A natural 1? That's destiny laughing."

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Critical outcomes apply only to resolution rolls.

By default:

• A natural minimum value on the resolution die is a critical failure
• A natural maximum value on the resolution die is a critical success

Criticals are properties of the base resolution die only. Modifiers, secondary dice, or later adjustments do not create or suppress critical outcomes.

Critical Effect Examples

The magnitude roll (d4) produces four levels: Normal (1), Minor (2), Notable (3), Major (4). But what do these mean in practice?

The engine provides examples. Content chooses interpretation.

For Damage:

For Duration:

For Area/Targets:

For Healing:

These are starting points, not mandates. Different effects scale differently. A critical hit with a sword might double damage. A critical success on a charm spell might double duration. Content creators choose the interpretation appropriate to each effect.

"Four outcomes. Infinite interpretations. The die tells you HOW good. You decide what good means."

Contested Resolution

When two entities oppose one another directly, each performs a resolution roll.

The final resolution values are compared:

• The higher value succeeds
• The lower value fails

Each side resolves its roll independently.

"When all else fails and you're still tied? I'm your die. Heads or tails, friend."

If the final resolution values are tied, and all reactions or instantaneous responses have been exhausted, the tie is resolved using a d2.

This represents a true binary outcome with no modifiers.

When Dice Are Not Rolled

Dice are rolled only when uncertainty and consequence intersect.

If an outcome is certain, or if no meaningful consequence exists, no roll is required.

Automatic success and automatic failure are valid outcomes when appropriate.

Notation Reference

Where formal dice expressions, probability descriptions, or roll structures are written in TDGS documentation, they may be expressed using the Dice Expression Language (DEL).

DEL is a descriptive notation used to communicate dice mechanics clearly and unambiguously.

DEL is not required to play TDGS, nor is it required for an implementation to support it directly. Its use in documentation is intended to improve readability, consistency, and machine interpretability.

The DEL specification can be found at: tacticaldice.com/delspec

Deferrals and Dependencies

This document intentionally does not define:

• Difficulty values
• Modifiers
• Character attributes
• Skills
• Progression
• Damage or harm
• Action economy
• Narrative interpretation

Some systems may modify resolution rolls. These systems are defined in later documents.

One such system is Luck, which is defined separately and does not alter the neutral behavior of dice themselves.

Status

This document defines the foundational rules for dice and uncertainty in TDGS.

All later mechanics must conform to the rules established here.

Changes to this document should be rare, deliberate, and backward compatible whenever possible.