The Ōyu Stone Circles was discovered in 1931. It was made about 4,000 years ago, around the same time as the Isedōtai site. With more than 8,500 stones used, it is the largest stone circle in Japan.

Along with the pottery and clay figurines, mysterious “clay tablets” were also excavated at this site. It kind of looks like a humanoid mascot character, but take a look for yourself and see what you think. What does this tablet represent, anyway?

Look at the holes and their placement. The one in the middle could be a mouth and the two holes on the top sides could be a pair of eyes. Then there are three on the right side and four on the left side, with five holes down the middle and six more on the back where ears could be. Could it possibly be dice? But if it were to represent numbers, that would mean that Jomon people understood the concept.

These kinds of clay tablets have only been found in the Ōyu Stone Circles. Was it pure coincidence or is there a hidden meaning behind it?