← Session Zero
EN RU
Old-School Essentials hero art
Necrotic Gnome / Gavin Norman

Old-School Essentials

"The dungeon doesn't care about your backstory. It cares about your torch."

Diced20 + стандарт
Players2–6
Prep~10 min
Foundry VTTCommunity
Complexity
What is this system

Old-School Essentials is the gold-standard retroclone of the 1981 B/X Dungeons & Dragons rules. Designer Gavin Norman took those rules and made them even clearer: reorganized, cross-referenced, and laid out so precisely that any rule you need is findable in seconds. This is not a nostalgia trip. It's the best version of a brilliantly simple game that was already perfect.

Setting

OSE is setting-agnostic — the rules support any flavor of fantasy, from sword-and-sorcery pulp to dark fairy tales to gonzo science-fantasy. The implied world is a dangerous wilderness dotted with crumbling dungeons, corrupt city-states, and ruins of fallen empires. Player characters are treasure-hunters first and heroes second, if ever.

What it looks like at the table
Third level of the dungeon. The map shows a door at the end of the corridor. The Referee rolls in secret — reaction check for the orcs behind it. A twelve: friendly. You could fight. Instead you parley. They want safe passage to the surface. You want the idol in room 14. A deal is struck. Ten minutes later, torches guttering, encumbered with gold, you hear something large moving in the dark behind you — something that wasn't on the map.
Playstyle
Exploration Survival Sandbox Combat Fantasy
Key mechanics

Dungeon Procedures

Every 10 minutes underground is a Turn. Each Turn: check for wandering monsters, track torch burn, manage noise. Time pressure is a resource. Light is a resource.

Reaction & Morale Rolls

Monsters aren't pre-programmed to fight. A 2d6 reaction roll determines if they're hostile, curious, or open to bargain. Morale rolls decide when they flee.

Ascending & Descending AC

OSE ships with old-school descending AC and THAC0 plus optional ascending AC rules side-by-side. Every stat block works for both systems.

Modular Design

Genre Rules, Class options, Advanced Fantasy expansions — OSE is built as interchangeable modules. Classic B/X core plus Advanced classes? Done.

What people say
This is about as perfect a set of old school rules as we've encountered – light, fast, streamlined, concise and polished to gleaming.— Stu Horvath, Unwinnable (Vintage RPG, Feb 2020)
As a dungeon master, it's a dream come true: fewer rules to juggle, easier to find the ones I do forget.— Matt Thrower, There Will Be Games
Art & materials
Free resources

Written and curated by Kejid — TTRPG player & GM

Similar systems
Vote on Old-School Essentials with your group →

Open in Session Zero to let every player vote and see the results.