pp. 90-91

Pottery from the middle Jomon period. It is thought that the middle Jomon period had the largest population inferring from the number of excavated sites, which is the most numerous throughout the entire Jomon period. Both pieces were made at the heart of the cultural area during this prosperous period.

2 (p. 91):
This pottery is referred to as yukotsubatsuki pottery. It has a belt-shaped rim with holes perforated at regular intervals.

As for the reason for having perforated holes, opinions are divided. One supposition is that it was for tightening a drum-skin, another is that it was to seal the pot for sake brewing. And yet another conjecture suggests that the holes are simply decoration that were placed in the upper area to not interfere with the pot’s practical usage.