D20 System
In 2000, Wizards of the Coast released a role-playing game system named after a twenty-sided die. Three primary designers shaped this new framework: Jonathan Tweet, Monte Cook, and Skip Williams. Richard Baker also contributed significantly to the project alongside Peter Adkison, who served as president at the time. Many observers credit Jonathan Tweet with establishing the basic resolution mechanic. He noted that other team members already possessed a core mechanic similar to his own when he joined the design group. This approach drew inspiration from systems like Ars Magica, which Tweet had previously created. The goal was to unify rules that varied wildly in earlier editions of Dungeons & Dragons. Prior versions used different dice for different actions and sometimes favored high numbers while others preferred low ones. The new system aimed to replace these inconsistencies with a single method for resolving all player actions.
A player rolls a twenty-sided die to determine success or failure during gameplay. Modifiers apply based on six character attributes: Strength, Dexterity, Constitution, Intelligence, Wisdom, and Charisma. Additional bonuses come from skill levels in specific fields such as combat or stealth. Situational factors may further adjust the final result. If the total equals or exceeds a target number known as a Difficulty Class, the action succeeds. This Core Mechanic applies consistently across every type of interaction within the game. It replaced complex tables found in first-edition games and the THAC0 system used in second edition Advanced Dungeons & Dragons. Unlike universal systems like GURPS, this framework did not claim universality but instead adapted to fantasy settings. Publishers later modified it for modern or futuristic environments using separate documents called System Reference Documents. These included materials from books like Player's Handbook v3.5 and Monster Manual v3.5.
Ryan Dancey served as brand manager for Dungeons & Dragons when he proposed an open licensing strategy. He believed the strength of the game lay in its community rather than its mechanical rules. Dancey promoted what became known as the Skaff Effect, suggesting that other companies increased market leader success by expanding the genre. His theory held that too many competing systems weakened the entire industry. To counteract this, Wizards released two licenses in 2000 before third edition Dungeons & Dragons launched publicly. The Open Game License allowed any party to produce works derived from designated content without paying royalties. The d20 Trademark License let publishers use the official mark to show compatibility with core products. Unlike the OGL, the trademark license could be canceled by Wizards at their discretion. This dual approach enabled commercial and non-commercial creators to build upon the system freely while maintaining a recognizable brand identity.
Between 2000 and 2003, numerous companies began publishing supplements under the d20 license. Existing firms like Atlas Games and Chaosium used the system to boost sales of their proprietary games. New entrants such as Goodman Games, Green Ronin, Mongoose Publishing, and Troll Lord Games focused exclusively on d20 content. Electronic delivery methods emerged quickly to meet demand for affordable digital copies. Wizards expanded the system beyond fantasy genres with Star Wars Roleplaying Game in 2000 and d20 Modern in 2002. They later developed Urban Arcana Campaign Setting in 2003 and extended into science fiction with d20 Future in 2004. Historical settings arrived via d20 Past in 2005 before concluding with Dark•Matter in 2006. Third-party publishers built campaign settings around these genre books, including White Wolf's licensed version of Gamma World released in 2006.
In 2003, Valar Project announced plans to publish the Book of Erotic Fantasy using the d20 System Trademark License. Wizards of the Coast responded by adding a quality standards provision requiring compliance with community decency norms. This change prevented the book from bearing the official trademark despite its use of open game content. The publisher removed direct references to Dungeons & Dragons and issued the work under the Open Game License instead. Similar cases followed, such as Skirmisher Publishing’s Nuisances, which carried a warning label stating it was intended for mature readers only. These events highlighted that Wizards retained broad discretion over what qualified as legitimate material. Publishers grew wary of investing time and resources into products subject to sudden policy shifts. The incident damaged trust between third-party creators and the original licensor.
Wizards of the Coast unveiled an updated edition known as 3.5 at Gen Con 36 in August 2003. Many third-party publishers received little advance notice about the changes. Companies found themselves stuck with outdated materials before reaching their audiences. No update existed for the d20 trademark itself during this transition period. Between these crises, numerous publishers went out of business or abandoned the field entirely. Those who remained chose to drop the trademark in favor of publishing solely under the OGL. They realized they could create successful games without relying on core books from Wizards. Some even developed direct competitors using OGL-based frameworks. In 2008, Wizards revoked the original d20STL upon releasing fourth edition Dungeons & Dragons. A new license called the Game System License replaced it but lacked associated open content. Products based on earlier SRDs continued legally under the OGL alone.
Common questions
Who designed the D20 System released in 2000?
Three primary designers shaped this new framework: Jonathan Tweet, Monte Cook, and Skip Williams. Richard Baker also contributed significantly to the project alongside Peter Adkison, who served as president at the time.
How does a player roll for success or failure using the D20 System Core Mechanic?
A player rolls a twenty-sided die to determine success or failure during gameplay. Modifiers apply based on six character attributes: Strength, Dexterity, Constitution, Intelligence, Wisdom, and Charisma. If the total equals or exceeds a target number known as a Difficulty Class, the action succeeds.
What licenses did Wizards of the Coast release in 2000 for the D20 System?
Wizards released two licenses in 2000 before third edition Dungeons & Dragons launched publicly. The Open Game License allowed any party to produce works derived from designated content without paying royalties. The d20 Trademark License let publishers use the official mark to show compatibility with core products.
When did Wizards of the Coast publish Star Wars Roleplaying Game under the D20 System?
Wizards expanded the system beyond fantasy genres with Star Wars Roleplaying Game in 2000. They later developed Urban Arcana Campaign Setting in 2003 and extended into science fiction with d20 Future in 2004.
Why did Wizards of the Coast revoke the original d20STL in 2008?
In 2008, Wizards revoked the original d20STL upon releasing fourth edition Dungeons & Dragons. A new license called the Game System License replaced it but lacked associated open content.