Beginnings of the stone circles

In the early part of the later Jōmon period (approx. 4,000 years ago), the Ippoingi-ushiro square-shaped stone arrangements were built 250 m northeast of the Nonakadō stone circle and the Manza stone arrangements were built 110 m south of the Manza stone circle. It was also in this period that 12 dug-standing pillar buildings were built in a 54-m diameter circle with pit graves nearby in an area (F4 zone) 100 m north of the Manza stone circle.