This was how the thousands of people who built the burial mounds and did the diffrent types of bullding and manufacturing lived and worked. Most of the things that were placed along with the body in the burial chamber were made at the construction site. Those that weren't were manufactured and brought in from China, the Korean peninsula, and all throughout the Japanese archipelago. Archaeologists think that many of the smaller tombs were made after the Nintokuryo Tumulus was finished. Here, by looking at one of the small keyhole shaped tumuli, we can see the process used to construct burial mounds.
Workers pile up earth.
And set stones on the slopes. And then the remains of the deceased were placed in the burial chamber. The principal role in buildlng a tumulus was not played by the special materials, or even by administrators, but by the many unskilled laborers who did the actual building. And most or all of these people were assembled for the sole purpose of building burial mounds.