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 .
Yamanaka Castle
Yamanaka Castle was built by Hōjō Ujiyasu in the Eiroku era (1558–1577), to guard the western approaches to the clan’s primary castle, Odawara Castle. The site was also chosen for its strategic location overlooking the Tōkaidō, the main highway connecting the eastern provinces of Japan with the capital at Kyoto. Despite the growing tension between the Later Hōjō clan and Toyotomi Hideyoshi, only a modest attempt was made to strength the defenses of the castle. During the 1590 Battle of Odawara, Toyotomi Hidetsugu led a force of 70,000 warriors against Yamanaka Castle, which was defended by Hōjō Ujikatsu with only 4,000 troops. Despite the disparity in numbers, the Toyotomi forces took heavy losses, including one general, Hitotsuyanagi Naosue; however, the castle fell in only a half day of combat and most of its defenders were killed.