Innoshima Suigun Castle

The Murakami navy (Murakami Suigun) ruled the medieval Seto Inland Sea. The name is often linked with pirates, but they were in fact sea clans with advanced naval power and diplomatic skill, and for a long time they controlled shipping on the Inland Sea during the Sengoku period. Innoshima Suigun Castle stands where the Innoshima Murakami, one branch of the family, had its base.

The current building is a replica keep built in 1983, not a genuine medieval castle. Inside, it holds and displays documents, weapons, old papers and maps related to the Innoshima Murakami, and serves as a museum of the Inland Sea's naval culture.

The Murakami navy was a maritime power divided into three houses: Noshima, Innoshima and Kurushima. It peaked in the 15th and 16th centuries. The Innoshima Murakami were especially strong among the three and, based on Innoshima, controlled sea traffic on the Inland Sea together with the Noshima and Kurushima houses.

Their activities combined collecting tolls (and issuing passes), piloting ships through the Inland Sea's channels, and fighting at sea in wartime. Seen from today, they were something between pirates and a maritime business, deeply involved in the economy and politics of the region.

As Oda Nobunaga and Toyotomi Hideyoshi unified Japan, the sea clans lost their independence. On Innoshima, memories of the Murakami navy still survive in place names, shrines and legends. To learn more about the Noshima branch, visit the Murakami Kaizoku Museum on Oshima.

The exhibits are spread over several floors.

Weapons and armor

Replicas and records of weapons and armor said to have been used by the navy are on display. You can see how their gear was specialized for fighting at sea, built for mobility rather than for land battles.

Old documents and maps

Reproductions of sea charts and documents show how the navy knew and managed the shipping lanes of the Inland Sea. They reflect the clans' detailed knowledge of the sea's complex currents and channels.

Innoshima history

There are also materials on the island's industry, culture and modern history, so you get an overall picture of Innoshima's past.

The castle stands on Shiroyama, a hill in central Innoshima. From the top of the keep and the hill you can see the island's farmland and coastline and the islands of the Seto Inland Sea.

Little blocks the view from the summit, so it is worth visiting as a viewpoint as well as a historic site. It is easy to imagine the navy watching over the Inland Sea from high ground like this to keep control of the waters.

The castle is inland, a little away from the main Shimanami Kaido route (the blue line). By bike, you need to leave the route and climb a hill, but it is worth the detour if you are interested in history.

You can also come by ferry to Habu Port, taking the route from Onomichi directly to Innoshima. Combine the visit with other island sights and local food such as Hassakuya (hassaku daifuku). See the Innoshima cycling guide for the island route.