It is said that Ima Castle was built during the middle of the sixteenth century. It has many complex structures such as a yokobori and a kuichigai koguchi.
Koike Ietsugu built the castle between 1532 and 1155. However, when Mori Nagayoshi entered Mino Kaneyama Castle, Koike was expelled. After this, it is said that he went back to being a farmer. The structure of this castle is similar to that of Omori Castle.