This pier is recorded in the Oku Komyoen Annual Report issued in 1938 and it is believed that it was used for the construction of Oku Komyoen. The pier was used by wooden boats to connect the Mushiage Semizo area on the opposite shore (only 22m above sea level) and Oku Komyoen on Nagashima island. Both piers were referred to as “Semizo Pier” or “Semizo Ferry”. The pier on the island is made of stones. It was built in the shape of a trapezoid, and the length of the left side was 10.8m and that of the right one was 9.9m. The tip of this pier was damaged by typhoons and it is now less than half of the original size. There used to be a guard station to keep strict watch for patients trying to escape by crossing the narrow strait, but it no longer exists.
※This place was designated as registered tangible cultural properties of Japan.