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 .
Aya Castle
Aya was built from around 1331 to about 1334. Its name derives from the man who oversaw the construction of the castle, who referred to himself only as "Aya" (his real name was Koshiro Yoshito). His family ruled over the castle until the Muromachi period, when the head of the Itō clan took over Aya Castle. The Shimazu clan seized the castle following their victory over the Itō in 1577. The castle was then given to Niiro Hisatoki, one of the retainers for the Shimazu Clan. Toyotomi Hideyoshi conquered the castle for a short period ten years later. In 1615, however, the castle was destroyed due to a shogunal decree that every domain could have only one castle.