---
title: "Running a million-board chess MMO in a single process · eieio.games"
url: https://daily.dev/posts/running-a-million-board-chess-mmo-in-a-single-process-eieio-games-fj34qf09t
source_url: https://eieio.games/blog/a-million-realtime-chess-boards-in-a-single-process
type: article
source: "eieio.games"
published: 2026-03-31T12:29:41.739Z
updated: 2026-03-31T12:55:14.059Z
tags: ["webdev", "golang"]
reading_time: 30
upvotes: 0
comments: 0
language: en
---

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# Running a million-board chess MMO in a single process · eieio.games

**[eieio.games](https://daily.dev/sources/eieio-games)** · 30 min read · 0 upvotes · 0 comments

## Summary

A detailed technical postmortem on building One Million Chessboards, a real-time MMO where 150,000 players made 15 million moves on a 1000x1000 grid of chess boards running in a single Go process. Covers the full architecture: a dense 8000x8000 uint64 array protected by a single RWMutex, zone-based move distribution to avoid O(N²) fan-out, protobuf+zstd serialization for bandwidth efficiency, Cloudflare caching for global data, and disk persistence via board duplication. The most technically challenging part was implementing rollback netcode on the client — optimistically applying moves immediately and maintaining a dependency graph to unwind conflicting moves. The author also reflects on game design mistakes: the lack of an awe-inspiring 'many players are here' moment and design decisions driven by scale rather than fun.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://eieio.games/blog/a-million-realtime-chess-boards-in-a-single-process>

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---

Tags: [#webdev](https://daily.dev/tags/webdev), [#golang](https://daily.dev/tags/golang)

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