Kaiyomaru is the name of an old wooden warship. The edo bakufu government ordered the ship to a Dutch maker and finished to make in 1866. The ship was one of the largest wooden warship at that time with dimensions 73 m long, and 45m high. A 410 HP steam engine was equipped. The ship sank off the shore of Esashi, only 1 years after arriving at Japan in 1867. The ship was reconstructed in 1990 and operated as a museum.