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 .
Sannohe Castle
The actual date of Sannohe Castle’s foundation is unknown; however, it was one of a series of fortifications established by the Nanbu clan in the late Kamakura period or early Muromachi period when the clan relocated its seat from Kai Province to Mutsu Province and started to secure its control over the frontier Nukanobu District. The clan residence remained at nearby Shōjujidate Castle in what is now the town of Nanbu until that fortified house was destroyed in an uprising in June 1539. The 24th hereditary chieftain of the clan, Nanbu Harumasa, relocated his seat to nearby Sannohe Castle.