Basic Role-Playing

Basic Role-Playing (BRP) is a generic tabletop role-playing game system published by Chaosium. It uses a percentile, skill-based resolution mechanic in which players roll a 100-sided die and attempt to roll equal to or less than a target number derived from a character’s skills or characteristics. First released in 1980 as a short introductory booklet derived from RuneQuest, BRP has served as the underlying engine for many Chaosium games, including Call of Cthulhu, Stormbringer, and RuneQuest itself, and has been published as a standalone multi-genre toolkit. The system has no default setting and generally uses no character classes or levels; characters improve by using skills and increasing individual abilities.

History

BRP originated in the late 1970s with RuneQuest, the role-playing game set in Greg Stafford’s world of Glorantha. RuneQuest, first published in 1978, introduced a percentile skill system and characteristics such as Strength, Constitution, Size, Intelligence, Power, Dexterity, and Appearance. In 1980 Chaosium released Basic Role-Playing as a short, generic booklet that extracted the core RuneQuest rules for use without a specific setting.

In 1981 Chaosium adapted the system for Call of Cthulhu, adding a Sanity mechanic and simplifying or modifying several rules for horror play. Other Chaosium games using BRP followed, including Stormbringer, Hawkmoon, Ringworld, Elfquest, Superworld, and Nephilim. Because each game introduced its own modifications, the exact form of BRP varied from game to game.

A substantially expanded collected edition, Basic Roleplaying: The Chaosium System, was published in 2002. In 2008 Chaosium published the 400-page Basic Roleplaying hardcover, commonly called the “Big Gold Book,” which compiled many optional rules for different genres. In 2023 Chaosium released Basic Roleplaying: Universal Game Engine, a streamlined version of the system, under the Open RPG Creative License, allowing third-party publishers to use the engine.

Core mechanics

Characteristics

BRP characters are defined by a set of characteristics, typically seven or eight: Strength (STR), Constitution (CON), Size (SIZ), Intelligence (INT), Power (POW), Dexterity (DEX), and Appearance (APP) or Charisma (CHA). Some variants add Education (EDU) or other attributes. They are usually generated by rolling three six-sided dice, though some implementations use other methods, such as 2d6+6 for certain characteristics. Characteristics influence skills, hit points, damage bonus, resistance rolls, and other derived values. Power is often associated with magic, sanity, and spiritual force.

Skills and resolution

The central mechanic is the percentile roll: a skill is rated from 0 to 100 or more, and a player rolls a 100-sided die. A result equal to or lower than the skill indicates success. Difficulty can be adjusted by halving, doubling, or applying other modifiers. Many BRP games further divide success into levels, such as special success, often one-fifth of the skill, and critical success, often one-twentieth of the skill. Fumbles may occur on very high rolls.

Skills have base chances that depend on characteristics, and some skills may begin at 0 or be unavailable to a character. Advancement usually occurs through experience: after using a skill successfully in a meaningful situation, a player may check it and later attempt to roll above the skill to improve it by a small amount.

The older resistance table, used in many BRP games to pit characteristics against one another, gives a target number by a formula such as 50 + (active characteristic × 5) − (passive characteristic × 5). Later versions often resolve such situations with opposed skill or characteristic rolls instead.

Combat

Combat in BRP is typically resolved through attack, defense, and damage rolls. Characters may attack with weapons or unarmed; defenders may parry, dodge, or rely on armor. Initiative is often determined by Dexterity ranks or strike ranks, depending on the implementation, and actions may occur in order from fastest to slowest. Damage is usually rolled for each weapon and modified by a damage bonus derived from Strength and Size. Armor subtracts from damage, and damage reduces hit points, which may be tracked for the whole body or separately by hit location, as in RuneQuest. Combat is often lethal, and many versions include optional rules for major wounds, bleeding, and shock.

Magic and powers

BRP supports multiple power systems, often presented as optional modules. Common magical traditions include spirit magic or battle magic, divine magic, and sorcery, each with different mechanics. Other options include psychic abilities, mutations, superpowers, and sanity. The Sanity mechanic from Call of Cthulhu, for example, has been incorporated into the generic BRP toolkit as an optional system for horror settings. The modular approach allows game masters to combine or ignore systems to fit a specific genre or campaign.

Distinctive features

BRP is notable for its skill-based advancement, lack of character classes and levels, and flexible, modular rules. A character is primarily defined by what they can do rather than by an archetype. The percentile roll is transparent and easily learned. The system tends to produce relatively fragile characters, especially in combat, which encourages planning and realistic consequences. Because the rules emphasize percentages and characteristics rather than a fixed setting, BRP can be used for fantasy, historical, horror, science fiction, superhero, and modern campaigns.

Games and settings using BRP

Many role-playing games use BRP or a close derivative. RuneQuest, the original source, is the primary fantasy implementation set in Glorantha. Call of Cthulhu, based on the writings of H. P. Lovecraft, is one of the most widely played BRP games and introduced the Sanity system. Stormbringer and Elric! adapt Michael Moorcock’s fantasy works. Other Chaosium BRP games include Hawkmoon, Ringworld, Elfquest, Superworld, and Nephilim.

Beyond Chaosium, several d100 systems derive from BRP. Mongoose Publishing’s editions of RuneQuest and Legend, The Design Mechanism’s Mythras, and the OpenQuest and Revolution d100 systems all trace their mechanics to the BRP tradition. Delta Green uses a BRP-derived system for modern cosmic horror.

Editions

The first Basic Role-Playing was a 16-page booklet published in 1980. It presented the core RuneQuest-derived rules without a setting. A substantially expanded edition, Basic Roleplaying: The Chaosium System, appeared in 2002, collecting material from various Chaosium games. In 2008 Chaosium published the 400-page Basic Roleplaying hardcover, often called the Big Gold Book, which compiled many optional rules for different genres. In 2023 Chaosium released Basic Roleplaying: Universal Game Engine, a streamlined version of the system, under the Open RPG Creative License, allowing third-party publishers to use the engine.

Influence and reception

BRP has been influential in the design of percentile-based role-playing systems. Its simple, adaptable core has been praised for ease of teaching and improvisation, while the modular options support many different genres. Some critics note that the large number of optional rules can make the system feel fragmented or require significant preparation. The combat rules, particularly with hit locations and major wounds, are often described as deadly compared with class-based, level-based games.