Photo of Higashinoyama by IR.

Higashinoyama is Eastern Mountain. It is due east of the valley where the Iwaya-Iwakage and the Senkoku-ishi megalithic clusters are located. There are two 9-meter long megaliths lying on the ground. They are aligned with the sun rising over the mountains on winter solstice morning. Don’t you think it is quite unusual for an astronomical site in the mountains to observe the winter sun?