We collected over 2,500 14 C dates from nine different prefectures: Tokyo, Kanagawa, Saitama, Chiba, Ibaragi, Tochigi, and Gunma (aggregated as Kanto region), Aomori, and Hokkaido (Fig 1). We also removed 14 C dates based on ples (i.e. shell and fishbone), as well as charred remains with high ? 13 C that might be potentially affected by a reservoir effect (i.e. >-24‰, given a range –24.0 ± 0.7 for terrestrial mammals and –25.9 ± 2.0 for C3 plants presented in ; a more conservative approach with a threshold set at -26‰ did not show major how to use jackd qualitative differences in the results, see S1 File). We excluded sites dated to Incipient and Initial Jomon periods (when the degree of sedentism was significantly lower), and those associated with the Final Jomon (when the overall sample size was too small in the Kanto region). We thus limited our analysis between the Early and the Late Jomon period, excluding all 14 C dates outside the interval 7,500
2,500 14 C years BP. The final sample size (n = 1,433; see Fig 1 for site distribution) used for the analysis was 406 14 C dates from 47 sites in the Kanto region, 432 14 C dates from 58 sites in Aomori Prefecture, and 595 14 C dates from 82 sites in Hokkaido.