Middle Jömon era (c. 3500-2500 B.C.) ceramics are characterized by elaborate decoration and many pieces seem more suited for ceremonial purposes than for eating or cooking. Unlike pots before c.5000 B.C., pots of the "Early" (5500-3500 B.C.) and "Middle" Jömon (3500-2500 B.C.) eras are usually flat-bottomed, suggesting that they were used indoors and placed on floors.
This example, from the Tokyo area, is decorated with human faces and hands.