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 .
Okayama Castle
Construction of Okayama Castle was started in 1573 by Ukita Naoie and completed by his son Hideie in 1597. Three years later, Hideie sided with the ill-fated Toyotomi Clan at the Battle of Sekigahara, was captured by the Tokugawa Clan and exiled to the island prison of Hachijo. The castle and surrounding fiefdoms were given to Kobayakawa Hideaki as spoils of war. Kobayakawa died just two years later without leaving an heir, and the castle (and fiefdom) was given to the Ikeda Clan, who later added Kōraku-en as a private garden.