Map: GSI Japan Sagara Castle was the short-lived domain center built for Tanuma Okitsugu at the height of his political power. Its construction, begun in 1768, was accompanied by roads, bridges, port activity, and a reorganized town. Makinohara City dates completion to 1780, while Kaizuka’s account gives 1779. After Tanuma fell, the shogunate confiscated the property in 1787 and dismantled the castle in early 1788. No keep or palace survives. The former enclosures now contain a municipal museum, schools, civic land, markers, trees, and altered waterways. The site's historical force comes from that abrupt sequence: ambitious construction, barely occupied completion, punitive erasure, and later local recovery of a politician's contested reputation.
