This was due to the difference in burial posture (Crouched burial are often found in a hole-shaped grave during the Jomon period, on the other hand full-length burial was common in a hole-shaped grave during the Yayoi period.)
これは、埋葬姿勢の差異に由来するものと考えられる（縄文時代の土壙墓には屈葬が多く認められる一方、弥生時代の土壙墓は伸展葬が一般的である）。