Karatsu, Saga
Due to its proximity to mainland Asia, Karatsu has long been known as a stopover to Korea and China.Under ritsuryō, the current city area was part of the Hizen Province. In 1591, on the coast of the northern part of the city (formerly the town of Chinzei), Nagoya Castle was constructed. The following year, it became the location from which the Imjin War was launched by Toyotomi Hideyoshi. In the middle of 1593, Terasawa Hirotaka created the Karatsu domain and began governing it. In 1602, replacing Nagoya Castle, Karatsu Castle was constructed in what is now the heart of Karatsu. The tower of Karatsu Castle was built in 1966 .
Ōzu Castle
Ōzu Castle was constructed in 1331 by Utsunomiya Toyofusa. However, the structure as represented now was built sometime between 1585–1617. During this period, the castle was controlled by a number of lords, including Wakisaka Yasuharu, Kobayakawa Takakage, Tōdō Takatora, and Toda Katsutaka. In 1617, the castle was occupied by Katō Sadayasu and, until the Meiji Restoration, the castle remained under control of the Katō clan. In 1888 the keep was destroyed by a fire, though the two "yagura", or towers, that were connected by corridors to the keep were saved. What remained of the castle survived World War II, even though the surrounding castle town was firebombed. In 2004 the keep was re-constructed, along with the corridors that connected the keep to the "yagura". A small museum about the history of the castle is housed in the keep and "yagura".