Chiba Castle located in Inohana, Chuo-ku, Chiba City was built by Chiba Tsuneshige in 1126 as a residence of the Chiba clan. In 1455, when Chiba Tanenao was defeated by Makuwari Yasutane, the castle was dismantled. The castle was located on the cliff at the end of a tonguing hill. The castle was protected by the steep cliffs on the south and west sides of the hill and the river running in the north. On the castle ruin site stands the donjon in the near modern style, which was built in 1967 and has been used as a city’s Folk Museum. The earthwork and part of dry moat remain to the northwest of the donjon. It is presumed that the castle had three main buildings in the middle age style. We can imagine the prosperity of the Chiba clan in those days from Dainichiji Temple, where the graves of the successive heads of the clan are placed, and many other temples in the city.