Last Updated: Aug 24, 2025

The Murakami Suigun

The “Pirates” of the Seto Inland Sea

This story was originally published on donnykimball.com and has been syndicated here on Medium.

Buckle up, everyone. Today, we’re diving into a group I’ve been itching to feature on this blog for what feels like forever. Known today as the Murakami Suigun, this band of seafaring warlords were basically Japan’s answer to pirate lords, ruling the waves of the Seto Inland Sea from their island strongholds in what’s now Ehime Prefecture. Yes, you read that right. Japan had pirates. And not just a handful of salty rogues either, but an entire maritime force that dominated regional waters for centuries. The Murakami were the main event in that long, often-overlooked chapter of Japanese history.

On that note, we’re going to be using the word pirate a lot in this article. For readers hailing from Western cultures, this might conjure up images of eye patches, frilly shirts, and rum from the Golden Age of Piracy. But Japan’s variant of these ruffians was a bit different. As was the case in most of the world across the long arc of history, piracy wasn’t a full-time job. Instead, it was more of a side endeavor that many coastal populations took up when the opportunity presented itself. Yes, this even applied to groups like the Vikings and the Barbary Corsairs.