Types of OSR Spellcasting Systems

This collaborative document outlines different OSR approaches to spellcasting systems.

Perceived problems with OD&D:

  • Boring

  • Vancian magic isn’t magical enough

  • Difference between spell levels and PC levels

  • Set spell lists

  • Doesn’t suit certain settings and types of campaigns

Types of spells

  • Set spell lists

    • By spell level

    • By player level (e.g., level 2 spell for level 2 caster)

    • By schools (e.g., Necromancy)

    • Level-less

  • New spells are discovered in game (as treasure or from other casters)

  • Improvised by player

Availability of spells

  • Spell slots

    • With slots per level

    • Overall number of slots (level-less)

    • Spells have physical form (e.g., scrolls) and take encumbrance slots

  • Any spell they know

    • Chosen by player

    • Chosen by player if they pass a check (e.g., Intelligence)

    • Determined randomly

  • Casting has a cost

    • Time: Spellcasting takes 2-3 rounds

    • Reduces hp

    • Mana cost

Success of spells

  • Target, if any, gets a saving throw

  • Caster rolls for success

  • Caster failure results in anything from magical side effects to catastrophes

  • Magic Dice (MD) per level, with option to roll as many or as few as you wish (GLOG) but with doubles result in a side effect and triples result in a catastrophe


  • Jeffrey Henning

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