---
title: "Basic Roleplaying"
version: "0.1.0"
slug: "brp"
players: "2–6"
duration: "60–240 min"
age: "14+"
tagline: "The percentile-skill engine behind Call of Cthulhu, RuneQuest, and Pendragon"
type: "rpg"
status: "live"
updated: "2026-07-22"
published: true
variants: false
how_to_play: "Roll percentile dice against your skill ratings to determine success. Characters are defined by characteristics (Strength, Dexterity, etc.) and skills, not classes. One player is GM, others are player characters."
mechanics: [dice, narrative, combat, exploration, skill-based]
complexity: moderate
related: [dnd-5e, pathfinder-1e, cairn, dungeon-world]
theme:
  surface: light
  tint: neutral
  texture: none
  cover: cosmic
  typography: modern
  accent: crimson
  section-divider: "☉"
engine:
  topology:
    type: none
  content:
    source: data/
    schema:
      type: category-list
---

<div class="section">

## Basic Roleplaying

A generic percentile-skill roleplaying engine, the design core beneath Chaosium's Call of Cthulhu, RuneQuest, King Arthur Pendragon, and other game lines. There are no character classes or levels: a character is a set of characteristics (Strength, Constitution, Size, Intelligence, Power, Dexterity, Appearance) and a list of skills, each rated as a percentage chance of success. One player acts as gamemaster (GM) while the rest play player characters (PCs).

This is the free, generic 2020 System Reference Document — the core toolkit only. It has no magic system and no bestiary of its own: Chaosium's specific settings built on BRP (Call of Cthulhu's Sanity and Mythos, RuneQuest's Runes and Rune Magic, Pendragon's Glory and Passions, etc.) are separate products and are explicitly excluded from this SRD as Prohibited Content under its licence.

**Licence:** BRP Open Game License, Version 1.0.
**Attribution:** Basic Roleplaying © copyright 1980–2020 Chaosium Inc. Authors, original rules: Greg Stafford, Steve Henderson, Warren James, Steve Perrin, Sandy Petersen, Ray Turney, and Lynn Willis; developed by Jason Durall, James Lowder, and Jeff Richard. Basic Roleplaying and the BRP logo are trademarks of Chaosium Inc., used with permission. Source: [brp.chaosium.com](https://brp.chaosium.com/basic-roleplaying/).

</div>

<div class="section">

### Rules

- [Introduction](rules/introduction/) — what roleplaying is, session/scenario/campaign length, dice, the gamemaster's job
- [Character Creation](rules/character-creation/) — characteristics, derived stats, skills, professions, equipment
- [System](rules/system/) — the core percentile roll, success/failure, opposed rolls, the resistance table, experience
- [Time](rules/time/) — narrative time, the turn, the combat round, skill time
- [Combat](rules/combat/) — the combat round phases, attacking, parrying, dodging, weapons, armor, shields, damage, healing
- [Spot Rules](rules/spot-rules/) — ambush, backstab, cover, darkness, disease, falling, poison, and other situational rules
- [Sample Foe](rules/sample-foe/) — a fully statted Bear, as a template for building NPCs and monsters
- [Character Sheet](rules/character-sheet/) — Blank character sheet (printable) with interactive generator

</div>

<div class="section">

### Reference Tables

Machine-readable JSON for skills, professions, and combat gear. See the [data index](../../games/brp/data/index.md) for the full list.

- [skills.json](../../games/brp/data/skills.json) — the 56-skill list with base chances
- [professions.json](../../games/brp/data/professions.json) — 12 sample professions and their skill lists
- [weapons.json](../../games/brp/data/weapons.json) — melee and missile weapon statistics
- [armor.json](../../games/brp/data/armor.json) — armor types, points, and skill modifiers
- [shields.json](../../games/brp/data/shields.json) — shield statistics

</div>