* Image is for illustrative purposes only.Nemuro Peninsula Chashi Sites
根室半島チャシ跡群
Nemuro Peninsula Chashi Sites is a historic castle in Hokkaidō dating from the 16th to 18th century, whose lord was Ainu People.
Overview
Overview
The Nemuro Peninsula Chashi Sites are a group of 24 Ainu fortress ruins (chashi) located in Nemuro City, Hokkaido, collectively designated as a National Historic Site and listed as No.1 among the Japan 100 Fine Castles. "Chashi" means "fenced enclosure" in the Ainu language. Built between the 16th and 18th centuries, these sites perch on cliffs overlooking the Sea of Okhotsk on the northern part of the Nemuro Peninsula, making them the easternmost and northernmost castle ruins in Japan.
History and Cultural Background
Chashi served multiple purposes beyond military defense — they were used for surveillance, religious ceremonies, community gatherings, and reconciliation rituals. As conflicts and trade with Wajin (Japanese) intensified from the 17th century onward, the Ainu people established these strongholds to build their own defensive network. Two sites — Notsukamaf Nos. 1 and 2 and the Onnemoton Chashi — are currently open to visitors, with excavations yielding pottery, stone tools, and iron artifacts.
Structure and Features
The chashi exploit natural clifftops as their primary defensive advantage, combining earthen ramparts and dry moats. Built without stone walls, their layouts reflect a uniquely Ainu architectural tradition shaped by the terrain. The 24 sites cluster along the northern coast of the peninsula, preserving evidence of Ainu settlement patterns and trade routes of the era.
Connection to Swords
From the 17th century onward, iron implements and swords circulated through northern trade routes as part of Ainu-Wajin exchanges and conflicts. Excavated iron artifacts from the sites document the flow of weapons and metal goods through Ainu society. During the Edo period, the Matsumae Domain used swords and bladed weapons as trade goods with the Ainu, reflecting the deep connection between swordsmanship culture and northern frontier history.
Access and Current Status
Approximately 20 minutes by car from central Nemuro. The Notsukamaf Chashi sites are located near Nemuro City's Meiji Park and are free to visit. Accessible from JR Nemuro Station by bus or taxi. Related artifacts are displayed at the Nemuro City Museum of History and Nature.
Connection to Swords
Swords circulated via northern trade routes in Ainu-Wajin exchanges from the 17th century. The Matsumae Domain used bladed weapons as trade goods; excavated iron artifacts document metal goods distribution in Ainu society.
Highlights
- Easternmost and northernmost castle ruins in Japan
- Japan 100 Fine Castles No.1
- 24 Ainu chashi ruins (National Historic Site)
- Unique Ainu defensive architecture atop ocean cliffs
* Opening hours and admission fees are subject to change. Please check the official website before visiting.