大和時代
Over the course of the Yamato period, in the early centuries of the establishment of a Japanese state, a great number of Korean-style fortresses (朝鮮式山城, "Chōsen-shiki yamajiro") were constructed in Japan. Old fortresses dating to the 8th century and earlier can be found all over western Japan. Many of these sites have been identified with fortresses whose construction, repair, and destruction are described in detail in ancient chronicles such as "Nihon Shoki" and "Shoku Nihongi". According to some interpretations of these texts, these fortresses were built under the guidance of, and at the orders of, various members of the Korean nobility or royalty.