The Kaichi school building, finished in 1876, is one of the oldest surviving Western-style schools in Japan and was designated a National Treasure in 2019. The architect, Tateishi Seijū, had never been abroad — he learned what he could from photographs and translated descriptions, and the result is a charming mash-up of Japanese carpentry techniques and pseudo-baroque flourishes, with an octagonal lantern tower and cobalt-blue glass detailing.
Inside there is a museum of Meiji-era education, with classrooms preserved much as they were. A short walk north of the castle.