Original Dungeons & Dragons vs Worlds Without Number

Compare Original Dungeons & Dragons and Worlds Without Number side by side. See differences in complexity, dice, genre, and more.

	Original Dungeons & Dragons	Worlds Without Number
Genre	Fantasy	Fantasy
Tags	Classic Fantasy, Dungeon Crawl, Exploration, Sandbox, Random Tables, Vancian Casting, Descending AC, Domain Management	Sandbox, Exploration, Faction Play, Strong GM Support, Gritty, Classic Fantasy, Random Tables, Hexcrawl, Low-Prep, Domain Management
Core Mechanic	Ability scores are rolled on 3d6, and combat uses a d20 attack matrix keyed to class or Hit Dice and Armor Class. Initiative uses dice, saving throws use class-and-level tables, and spellcasters have limited spells remembered per adventure.	Skill checks roll 2d6 plus the relevant skill level and attribute modifier against a difficulty. Attacks roll d20 plus base attack bonus, combat skill, and attribute modifier against the target's Armor Class. A missed melee attack can still inflict Shock damage when the target's AC is low enough.
Dice	d20	2d6 / d20
Complexity	High	Medium
Availability	Paid	Free core rules
Runnability	3 of 5 book tools	5 of 5 book tools
License	Proprietary	CC0 1.0 Universal (SRD 1.0); proprietary core books
Third-Party Publishing	Not yet researched	Commercial publishing allowed — Worlds Without Number System Reference Document (SRD 1.0) under CC0 1.0 Universal
Summary only, not legal advice. Check current terms before publishing.
Publisher	Tactical Studies Rules	Sine Nomine Publishing
Year	1974	2021
Languages	English	English
Best For	Groups who want an early fantasy campaign game with dungeon expeditions, open wilderness play, and substantial referee adjudication. It fits tables willing to choose or adapt procedures when the rules leave room.	Groups who want an open fantasy sandbox where their own goals drive play. Faction turns and campaign-building tools keep the world moving between sessions.
Highlights	A class-and-level attack matrix turns a d20 roll into a direct Armor Class result. Separate dungeon, wilderness, aerial, and naval procedures let a campaign expand beyond expeditions. Referee-facing dungeon design and stronghold rules support an open campaign beyond a prepared scenario.	The campaign chapter turns worldbuilding into procedures, with tags and tables that keep sandbox preparation to one session ahead. Faction turns let rival powers act between sessions, so the setting changes even when the players are elsewhere. Shock damage keeps melee misses meaningful and makes armor and shields matter in close combat.
Considerations	Classes, race limits, spell lists, and attack matrices impose a specific early D&D structure. The original rules distribute important procedures across separate subjects rather than one universal task rule. Running strict 1974 requires separating the original rules from Chainmail references and later compilation material.	Combat resolution is deliberately simple, with positioning and Shock carrying most of the tactical weight. The rules assume a sandbox campaign and offer little structure for pre-planned story arcs. Social conflict is handled by skill checks and GM judgment rather than a dedicated subsystem.