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Call of Cthulhu studio opens up Basic Roleplaying System to other tabletop RPG creators

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The Basic Roleplaying System, which powers Call of Cthulhu, RuneQuest and other tabletop RPGs, now has an open game licence, allowing budding game designers to create their own worlds and games using the roleplaying ruleset.

Like Dungeons & Dragons - which has its own Open Game License - the Basic Roleplaying System uses a set of polyhedral dice ranging from four-sided to 100-sided. However, unlike D&D’s d20 system, BRP’s d100 gameplay predominantly relies on percentile rolls, requiring two ten-sided dice to calculate: one to clarify the ‘tens’ and another the ‘ones’. For example, if you rolled a three and a nine, the first number would be 30 and the second 9, giving you a result of 39.

Basic Roleplaying System was first used in Chaosium’s 1978 fantasy tabletop RPG RuneQuest. It then evolved into its own standalone ruleset in 1980 and was subsequently used in a raft of other Chaosium games, most notably the Lovecraftian horror RPG Call of Cthulhu - one of the best tabletop roleplaying games out there right now. Although it’s best known through Call of Cthulhu, the system can be adapted for all kinds of tabletop settings; for example, modern superhero RPG SuperWorld uses it.

Basic Roleplaying was the first RPG system to grant characters a full skill system that wasn’t linked to their in-game profession. This is reflected by an extensive amount of player character skills, ranging from the likes of art to literacy and psychotherapy. Instead of picking combat character class options, BRP offers players professions like doctor or soldier. As well as professional abilities, players have points to use in personal skills, allowing them to pick individual skills like Bargain or Weapon from the different professions regardless of their main role.

The Basic Roleplaying System open licence means that game creators and designers can use the ruleset to power their own tabletop RPGs, without the need for permission from publisher Chaosium. However, users are prohibited from using plots, story elements and characters that link to Chaosium tabletop RPG lines, including Call of Cthulhu, 7th Sea and the epic King Arthur Pendragon.

The latest edition of the Basic Roleplaying System is live now on publisher Chaosium’s website. No upcoming tabletop RPGs built on the Basic Roleplaying System have been announced yet, but some will presumably be on their way soon enough.

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