Overview & Philosophy
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 Appendix E: Resources for essential West Marches reading.
How to Use This Document
| Section | When to Read | What You’ll Find |
|---|---|---|
| Philosophy | First — understand the “why” | Five pillars, GM role, expedition structure |
| Session Zero | Before campaign start | History building, palette, Guild creation, player goals |
| Settlements | When founding towns or reaching new tiers | Collaborative settlement generation, factions, growth |
| Wilderness | When players explore between sites | Hex procedures, terrain, discoveries, travel |
| Dungeons | When players target a dangerous site | Rumor-driven generation, ecology, responsive threats |
| Quest Prep | Between sessions, after player declaration | Goal analysis, obstacle design, faction clocks |
| Running Sessions | During and after play | Adjudication, recording, post-session procedures |
| Wiki & Tools | Ongoing campaign maintenance | Wiki structure, templates, AI integration |
Start Here
First time reading? Read the Philosophy section completely, then jump to whichever section matches your current need. Quick reference? Use the navigation to jump directly to the procedure you need. 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 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
Optional but recommended: The worldbuilding games mentioned in Proven Solutions (Microscope, Ex Novo, etc.), 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.
A Note on Terminology
- GM = Game Master, Dungeon Master, Referee, Facilitator
- PC = Player Character
- Guild = The central settlement/organization where adventurers gather
- Expedition = A single session’s adventure arc (declaration → execution → return)
- Faction = Any organized group with goals
- Canon = Established world facts that all players can reference
- Generation = The process of creating new content
Core Philosophy
The Fundamental Principle
Content is generated responsively when players declare intent, not pre-generated in advance. Once established, it “always existed”—common knowledge available to all guild members.
Five Pillars of Western Horizon
1. Goal-Driven Play
Players bring goals, not reactions to GM hooks. Each character has concrete objectives they’re actively pursuing. The GM’s job shifts from “create interesting hooks” to “create interesting obstacles to what players already want.”
Why this works:
- Players are invested because they authored their own direction
- Eliminates “what do we do?” paralysis at session start
- Provides clear criteria for content generation
- Creates natural story through goal collision between PCs and factions
Goals vs. Hooks
Traditional play: GM creates hooks, players choose which to pursue. WH play: Players declare goals, GM creates obstacles to those goals. The inversion puts players in the driver’s seat while still ensuring interesting challenges.
2. Responsive Generation
Content is created when needed, not before. When a player posts “I want to investigate the ruins in the Thornwood,” that’s when you generate the dungeon. When they reach a new tier and need a larger settlement, that’s when you build the town.
Why this works:
- Eliminates wasted prep on content players never engage
- Reduces DM burnout from pre-building an entire world
- Ensures content is responsive to actual player interest
- Allows the campaign to grow organically
When Does "Responsive" Happen?
Not during the session. Responsive generation happens between sessions during prep. Player posts intent → GM generates content before session → Session runs with established content → Discoveries logged after session.
3. Collaborative Authorship
The GM doesn’t create the world alone. Players participate in worldbuilding at multiple stages:
- Session Zero: Everyone builds history, sets tone, establishes the Guild
- Settlement Building: Players help create towns, detail landmarks, define factions
- Dungeon Rumors: Player speculation about dungeons informs their actual contents
- Discovery: When players find something, they help name it, describe it, define it
Collaborative Principle
“Everyone is equal. We each have vast power to create and destroy. But once we make something, it belongs to all of us. No one owns anything.”
The GM’s Specialized Role
In collaborative authorship, the GM is still a storyteller—just no longer the primary author. Instead, the GM specializes in adjudication and simulation.
| Traditional GM | WH GM |
|---|---|
| Primary author of world and story | Co-author alongside players |
| Creates content proactively | Creates content responsively to player goals |
| Guides players through planned narrative | Adjudicates player interaction with established world |
| Reacts to player choices during session | Reacts to player declarations between sessions |
The GM’s authorship happens in three distinct modes:
1. Collaborative Creation (Between Sessions) — With players: running worldbuilding games, facilitating settlement creation, incorporating player ideas. Alone: using generation systems to build content responsive to declared player goals. This is where “what exists” gets authored.
2. Active Adjudication (During Session) — The referee role: making rulings on player actions within the established world. This is where “what happens” gets authored.
3. World Simulation (After Session) — The world reacts: advancing faction clocks, simulating consequences, updating the state of the world. This is where “what changes” gets authored.
Two Types of "Reactive"
Content Reaction (Between Sessions): Players declare “We’re going to the Thornwood Swamp” → GM reacts by prepping that location. This is asynchronous.
Adjudication Reaction (During Session): Players act “I want to swing from that chandelier” → GM reacts by ruling whether/how that works. This is synchronous.
Most traditional GMing advice addresses content reaction during play (“what if they go somewhere I didn’t prep?”). WH eliminates that problem through self-contained expeditions. The GM still needs adjudication skills, but not improvised content generation.
The Self-Contained Expedition Structure
| Phase | What Happens | GM’s Authorship Mode |
|---|---|---|
| Planning (Between Sessions) | Players discuss goals, post “We’re going to [location] to [achieve goal]“ | Collaborative Creation: Use generation systems to prep the declared location |
| Expedition (During Session) | Session starts en route, players execute plan, encounter prepped content | Active Adjudication: Rule on player actions, simulate consequences |
| Resolution (After Session) | Return to settlement, log discoveries, discuss next goals | World Simulation: Advance faction clocks, update world state, seed new rumors |
Why "Self-Contained" Matters
Traditional sessions often start with “What do you do?” and can go anywhere. The GM must constantly react to unknown player direction.
WH sessions are different: They’re going to the swamp. That’s not “on the way to the swamp”—that’s where they’re going. You prepped the swamp because they told you they were going there. During the session, you’re not surprised about where they are—only what they do when they get there.
This is why advice like “stalling tactics” or “back-pocket encounters” doesn’t apply to WH.
4. Canon Integration: “It Always Existed”
Once content is generated and played, it becomes permanent canon known to all guild members. The temple in the Thornwood? It always existed. The merchant prince who runs the harbor? Everyone knows about them.
How this works in practice:
- Content is added to the Guild Wiki (Obsidian or similar)
- Other players can reference it: “I heard there’s a temple in the Thornwood…”
- Future generation must not contradict established canon
- New content builds on rather than replaces old content
What "Always Existed" Means
It doesn’t mean the DM secretly planned everything in advance. It means once something appears in play, we treat it as if it was always part of the world. The generation method is invisible to players—they just see a coherent, persistent world.
5. Scale & Scope
A living world operates at multiple scales simultaneously. The Western Horizon needs generation procedures for each scale.
| Scale | Generation Need | Key Outputs |
|---|---|---|
| History | Shared past, defining moments, cultural touchstones | Eras, events, legends, conflicts |
| Settlement | Living towns with factions pursuing goals | Districts, power structures, development timeline |
| Locations | Specific places with sensory details and NPCs | Landmarks, residents, relationships, atmosphere |
| Wilderness | Travel between sites with emergent complications | Terrain, discoveries, dangers, waypoints |
| Dungeons | Dangerous sites with internal logic and threats | Layouts, denizens, treasures, ecology |
Problem-First, Not System-First
Each scale has specific problems to solve. The Western Horizon defines what makes a good solution rather than mandating specific systems. Later sections present battle-tested procedures that align with these principles—but alternatives work too if they solve the same problems.
But Why? Goals Over Hooks
The Bootstrapping Problem
Responsive generation requires player intent. But how can players form meaningful intent without knowing what exists? They can’t want “the moss from the swamp” without knowing there’s a swamp.
The traditional solution: The DM pre-generates content and offers it via hooks on a bulletin board. The problem with that: It puts creative burden back on the DM and makes players passive consumers.
The Inversion: Players Bring Goals, Not Reactions
The solution comes from The Game Master’s Handbook of Proactive Roleplaying by Jonah and Tristan Fishel. Instead of the GM creating hooks for players to react to, players arrive with goals and the GM creates obstacles.
| Traditional (Reactive) | Proactive |
|---|---|
| GM creates hooks | Players declare goals |
| Players choose from options | GM creates obstacles to goals |
| ”Here’s what’s available" | "What do you want?” |
| Story comes to players | Players pursue story |
| GM plans the adventure | Adventure emerges from goal collision |
What Makes a Good Goal?
Each player character should have three goals at any time (short-term, medium-term, long-term):
| Property | Why It Matters | Example |
|---|---|---|
| Player-authored | Investment comes from ownership | Player invents goal, not GM |
| Specific & achievable | You know when you’ve succeeded | ”Win the tournament in Songul” not “become stronger” |
| Has consequences | Failure must matter | ”…so Su-Li will marry me” |
| Non-repeatable | Stakes are real | Can’t just try again next week |
| Fun to pursue | Generates interesting play | Can imagine level-appropriate obstacles |
The Magic Question
Ask players: “What would it look like when you reach your goal?”
This helps players envision specific, achievable endpoints and often generates encounter ideas, NPC needs, and location requirements that feed directly into responsive generation.
Factions as the GM’s Party
Every faction should have concrete goals that overlap or conflict with player goals. Factions become “the GM’s party”—pursuing their own agendas between sessions, creating emergent pressure and obstacles.
| Faction Element | Purpose |
|---|---|
| Identity | What they do, who they are |
| Goals | What they want (specific, concrete) |
| Clocks | Progress toward goals (advances between sessions) |
| NPCs | Agents who pursue faction goals in play |
The key insight: Faction goals must relate to the same people, places, and events as PC goals. This ensures collision—and collision generates content.
Clocks: Between-Session Pressure
Borrowed from Blades in the Dark, clocks track faction progress toward goals:
- A clock is a circle divided into segments (typically 4 or 8)
- When a faction makes progress, fill a segment
- When full, the faction achieves their goal
- Clocks advance between sessions, whether players engage or not
This creates urgency without the GM authoring storylines.
The Bulletin Board Reconsidered
| Traditional Role | Proactive Role |
|---|---|
| Primary source of adventures | Supplement to player goals |
| GM-authored quest hooks | Window into faction activity |
| ”Choose your adventure” | Information marketplace |
| Required for play | Fallback for players without direction |
Two Modes of Content Generation
| Mode | Trigger | Depth | Example |
|---|---|---|---|
| Hook Seeding | Faction clocks advance, session aftermath | Shallow pointers | ”There’s a swamp to the northwest” |
| Content Realization | Player pursues a goal | Full generation | The swamp’s hexes, NPCs, dangers |
The Complete Picture
- Session Zero: Players create characters with 3 goals each. Factions are created with goals. GM identifies overlaps and conflicts.
- Between Sessions: Faction clocks advance. New rumors and consequences appear on the board. Players discuss goals and form intent.
- Player Posts Intent: “I want to find the assassin who killed my mentor.” This declares which goal they’re pursuing.
- DM Generates Content: Using responsive generation systems, the DM creates obstacles.
- Session Runs: Play happens with generated content.
- Aftermath: Discoveries become canon. Faction clocks advance. New goals emerge. Cycle repeats.
Why This Works
Players bring investment (goals). Factions provide opposition (conflicting goals). The GM provides obstacles, not storylines. Story emerges from the collision of goals—surprising everyone, including the GM.
How This Differs from Standard West Marches
Traditional West Marches assumes the DM pre-generates the entire world before play begins. The Western Horizon keeps the player-driven, open-table structure but adds:
- Responsive content generation instead of upfront world creation
- Collaborative worldbuilding instead of DM-only world design
- Goal-driven play instead of hook-driven play
- Faction clocks for between-session pressure
- System guidance for which procedures to use when
- Integration with modern tools (Obsidian wikis, Claude AI processing)
This Reduces DM Burden
West Marches campaigns are notorious for DM burnout. By generating content responsively, collaboratively, and in response to player goals, The Western Horizon makes West Marches sustainable for long-term play without requiring heroic prep efforts.
Guiding Principles for Collaborative Creation
- Everyone is equal. One person might facilitate, but they don’t have more control than others during collaborative creation.
- Don’t contradict what’s already established. New content builds on the foundation.
- Don’t coach or suggest on someone else’s turn. Let each person surprise you.
- Paint a clear picture everyone can visualize. Be specific and evocative.
- Players are more important than the game. Safety tools override all other rules.
What This Framework Provides
- Philosophy: The “why” behind goal-driven, responsive, collaborative play
- Problem definitions: Clear articulation of what needs solving at each scale
- Solution criteria: What makes a good generation procedure for WH
- Workflows: Player intent → content generation → session play → wiki documentation
- Proven systems: Battle-tested procedures that align with WH principles
- Integration points: How different scales hand off to each other
- Goal and faction frameworks: Practical tools for proactive play
- Templates: For wiki pages, session prep, and quick reference
It does not prescribe mandatory systems. Think of this as design principles with proven examples, not a rigid playbook.
Proven Solutions
The Western Horizon doesn’t prescribe specific systems—it defines problems and what makes good solutions. However, several battle-tested games align perfectly with WH principles.
Why These Systems?
Each system was selected because it: supports collaborative authorship, generates responsive content, creates factions with goals, respects established canon, and operates at its scale efficiently.
You can use these as written, adapt them, or substitute alternatives that solve the same problems.
| Problem Domain | What You Need | Proven Solutions |
|---|---|---|
| History & Culture | Shared backstory, cultural touchstones, defining moments | Microscope, Chronicle |
| Living Settlements | Towns with factions pursuing goals, districts with history | Ex Novo, Kingdom |
| Detailed Locations | Specific buildings with sensory details, memorable NPCs | Beak, Feather & Bone, Street Magic |
| Wilderness Travel | Terrain that matters, emergent complications, discoveries | Perilous Wilds, Hexmancer |
| Dangerous Sites | Dungeons with internal logic, ecology that reacts | Ex Umbra, Delve & Rise |
| Goal-Driven Structure | Player goal frameworks, faction clocks, obstacle design | Proactive Roleplaying |
Reactive vs. Proactive Tables
Many of these systems use random tables (roll 2d6, consult table). This doesn’t contradict responsive generation. The design language works whether you roll randomly or choose deliberately:
- Roll: Quick generation, surprising results, good for areas players barely mentioned
- Choose: Precise control, goal-aligned obstacles, better for player-declared destinations
The tables provide design vocabulary either way. What matters is that content is generated when players pursue goals, not whether you rolled or picked.
New to West Marches?
See Appendix E: Resources for essential reading on player-driven exploration, open tables, and the Guild model.