Octas is a Table Top Role-Playing game system based on the use of two 8-sided dice, numbered 0-7. It ostensibly uses the octal (base-8) numeric system, although this is largely hidden from players behind some simple conversion maths.

Below are the System Reference Documents (SRDs) needed to play all variants of Octas. They are provided free to use under the ORC licence.


  1. Licence
  2. Introduction
  3. Creating a Character
  4. Playing an Adventure
  5. Extended Rules



  1. Formula Summary: Common tables and formula used in-game.
  2. Information for Immigrants: Octas compared to other TTRPGs.
  3. All your base: Why base-8? (author's ramblings).
  4. Measure of a Something: Derivation of the Octas units of measurement.
  5. Miniature Play: Tokens and figurines for physical play.
  6. Playing Octas in Decimal .... and possibly other numeric bases.
  7. Playing Octas in (actual) Octal: Game-play for Mathematical Masochists!

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