Introduction
What Is The Western Horizon?
The Western Horizon is a design philosophy for running West Marches campaigns where players drive the story through their goals, the GM generates content responsively, and the world is built collaboratively.
Unlike traditional West Marches (where the GM pre-builds an entire world before play), WH generates content when players declare where they’re going and why. Unlike traditional campaigns (where the GM plans storylines), WH lets stories emerge from player goals colliding with faction goals.
The Core Insight
If players bring goals and factions pursue goals, the GM doesn’t need to author storylines. Create obstacles to player goals, let factions advance their own agendas, and story emerges naturally from the collision.
Who Is This For?
The Western Horizon is for GMs who want to run West Marches campaigns but:
- Don’t want heroic prep burdens — Generating an entire world upfront is exhausting
- Want player agency to be real — Not just “which hook do you bite?”
- Value emergent stories — Surprises for the GM too, not executed plans
- Want sustainable long-term play — Campaigns that grow organically without GM burnout
- Enjoy collaborative worldbuilding — The world belongs to everyone at the table
You don’t need to be running a West Marches campaign to use these principles—goal-driven, responsive, collaborative play works in any campaign structure. But WH is specifically architected around the West Marches model: open table, player-organized sessions, persistent shared world, exploration-focused play.
New to West Marches?
West Marches is a campaign style invented by Ben Robbins featuring:
- Open table: Variable player roster, no required attendance
- Player-organized sessions: Players coordinate, pick their party, declare their goal
- Persistent world: What one group discovers becomes canon for all
- Exploration focus: The frontier is dangerous and largely unmapped
- Guild structure: A central settlement where adventurers gather between expeditions
See 08 - Appendices for essential West Marches reading.
How to Use This Document
| Section | When to Read | What You’ll Find |
|---|---|---|
| 00b - Core Philosophy | First — understand the “why” | Five pillars, GM role, expedition structure |
| 01 - Session Zero | Before campaign start | History building, palette, Guild creation, player goals |
| 01a - Player Guide | Before first session | Player expectations, character creation, between-session rhythm |
| 02a - Settlement Overview | When founding towns or reaching new tiers | Collaborative settlement generation, factions, growth |
| 03a - Wilderness Overview | When players explore between sites | Hex procedures, terrain, discoveries, travel |
| 04 - Dungeons | When players target a dangerous site | Rumor-driven generation, ecology, responsive threats |
| 05 - Quest Prep | Between sessions, after player declaration | Goal analysis, obstacle design, faction clocks |
| 06a - Session Structure | During and after play | Adjudication, recording, post-session procedures |
| 07 - Wiki | Ongoing campaign maintenance | Wiki structure, templates, AI integration |
Start Here
First time reading? Read 00b - Core Philosophy completely, then jump to whichever section matches your current need. Quick reference? Each section is designed to stand alone.
What You’ll Need
- A TTRPG system — WH is system-agnostic, though examples use D&D 5E terminology
- 3-6 players minimum — West Marches works best with a larger pool (8-12+) but can run with fewer
- A communication platform — Discord, forum, or similar for between-session coordination
- A wiki or shared notes — Obsidian recommended, but any collaborative note tool works
- Time between sessions — WH assumes days or weeks between sessions for prep and coordination
Optional but recommended: The worldbuilding games mentioned in 00d - Proven Solutions, session recording and transcription tools, virtual tabletop if playing online.
This Is Not a Complete System
The Western Horizon provides philosophy and procedures for campaign structure. It doesn’t replace your TTRPG rules, nor does it include complete worldbuilding game procedures (you’ll need those source books for full details).
Think of WH as the architecture that shows how pieces fit together, not the pieces themselves.
Terminology
- GM = Game Master, Dungeon Master, Referee, Facilitator
- PC = Player Character (the adventurers)
- Guild = The central settlement/organization where adventurers gather
- Expedition = A single session’s adventure arc (declaration → execution → return)
- Faction = Any organized group with goals (guilds, cults, nations, families, etc.)
- Canon = Established world facts that all players can reference
- Generation = The process of creating new content (settlements, dungeons, etc.)