Jomon civilization continued in Japan until 300 BC and is divided chronologically into six periods: (Incipient Jomon) 11000- 7500 BC, (Initial Jomon) 7500 – 5300 BC, (Early Jomon) 5300 – 3600 BC, (Middle Jomon) 3600 – 2500 BC, (Late Jomon) 2500 – 1000 BC and (Final Jomon) 1000 – 300 BC.
The current research paper deals with the study of the site (Sanai Maruyama) which dates back to the time period 3500-2000 BC which is the (middle Jomon) period A large number of findings such as pottery, stone utensils, clay figures, jewelry made of jade beads, stone pots, arrowheads, stone grinding tools, remains of plant seeds, remains of marine bones were excavated, in addition to finding many dwelling pits, storage pits, tomb pits and columns for building reinforcement. The current research paper also aims to conduct an archaeological and analytical study of the site (Sanai Maruyama) during the middle Jomon phase. The site is regarded as a special national site for Japan in 2000, and the UNESCO world heritage site as part of the prehistoric Jomon group of sites of in Northern Japan in 2021.