Nicknamed Maizuru-jō (Dancing Crane Castle), this elegantly proportioned white castle (built 1608, rebuilt 1966 and refurbished 2017) is picturesquely perched on a hill overlooking the sea. Inside are antique ceramics, samurai armour and archaeological displays, amid walls lined with Karatsu-yaki (Karatsu pottery) tiles. Download the Karatsu Castle app to scan QR codes for detailed English descriptions of select pieces. The climb up the hill can be a slog, especially in muggy summer heat, but there's a diagonal elevator.
The views from the castle grounds are breathtaking: Karatsu Bay and the town of Karatsu lie below, making it easy to see why the location was such prime real estate for Lord Terasawa, a chief retainer to Toyotomi Hideyoshi.