Kijo Castle is a Korean-style fortress located on the 400m-high peak of Kijo. It is situated in what is today the Okayama Prefecture town of Sōja.

According to the 'History of Kijo', the castle is the origin of ogres, which appear in the legend of Momotaro. The castle is also believed to be the provenance of the same legend. There is a story that Ura, the prince of Baekje, came to Kibi and founded a country. Later he brewed up some mischief, and seized supplies as well as women and children to send to his country. As a result, people were terrified and named Kijo 'the castle of ogres'.

The fortress extends some 2.8km round on land of about 30 hectares. It is a perfect place for hiking, and from the peak, the whole country of Kibi can be seen.