Motifs and projections differ depending on the region.
1 (p. 94):
So-called Ka-en style (fire flame style) pottery. Found mainly in the Nakaetsu region of Niigata prefecture, this type of pottery has also been excavated as far north as Akita prefecture and as far east as Fukushima prefecture.
2 (p. 95):
Pottery that appeared in the region extending from the Kohu basin to the Santama area.
To gauge the time period and changes in Jomon society of that site, all shapes, motifs, patterns, and ornaments of excavated pottery are closely examined, as well as the number of pottery pieces.