Tosaminato

Tosaminato spreads across 55 hectares along the coast and shows earthen walls plus archaeological traces of seafaring activities from ancient times. The site preserves the remains of storehouses, residential quarters, and fortifications that once formed a major trading settlement.

The harbor settlement was active from the Heian to the Muromachi period under the Ando clan and served as a major trading point with Korea and mainland Asia. The decline began in the 16th century when trade routes shifted and the harbor basin gradually silted up.

Excavations at the site uncovered Chinese porcelain and roof tiles in Kyoto style, showing active trade between different regions during the 15th century. These finds indicate that the harbor settlement served as a meeting point for the exchange of luxury goods.

The site offers guided tours between July and October, with reservations required through the Goshogawara tourism department. Visitors should wear sturdy shoes since the terrain covers grass and uneven earthen paths.

Lake Jusan, which today separates the site from the Sea of Japan, was originally a sea inlet that formed the natural harbor. This geographical change occurred over centuries through sediment deposits and land uplift following earthquakes.