The Basic Roleplaying System Reference Document 1.0 (“BRPSRD1.0”) describes the rules of Basic Roleplaying. You may incorporate the rules as they appear in BRPSRD1.0, wholly or in part, into a derivative work, through the use of the BRP Open Game License, Version 1.0. You should read and understand the terms of that License before creating a derivative work from BRPSRD1.0.
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If you have questions about this licence, please reach out to Chaosium at licencing@chaosium.com