Asian Journal of Paleopathology Vol.6, 1–5, 2024
Received: February 8, 2024
Accepted: March 12, 2024
DOI: 10.32247/ajp2024.6.02

Case Study
Violence-related skeletal trauma in the Epi-Jomon period: A case study from the Koboro cave site in Hokkaido, Japan

Izumi Braddick, Daisuke Kubo, Hirofumi Matsumura, Rick J. Schulting

Abstract
　This study presents two newly identified cases of violent trauma on skeletal remains unearthed at the Koboro cave site in southwestern Hokkaido, Japan. Clear evidence of perimortem trauma was found on cranial (Koboro 1) and postcranial (Koboro 8) bones belonging to an adult male or males aged between 25–39 years old. Koboro 1 exhibits two injuries (one blunt force and one semi-sharp force) on its cranium, while two stone projectile points were found embedded in the right ilium and left eighth rib of Koboro 8. With no signs of healing in either case, the Koboro remains show evidence of violent death. In addition to macroscopic observations, computed tomography (CT) and 3D scanning were conducted on the postcranial injuries to estimate the directions of penetration of the stone projectile points in the bones. The position of the projectile lodged in the rib suggests that Koboro 8 was shot in the chest from diagonally right anteriorly, the arrowhead likely puncturing both lungs (or liver and left lung) and possibly piercing the heart. It is unclear whether or not the Koboro 1 and Koboro 8 remains belong to the same individual. These new trauma cases provide further insights into the types of injuries and violence present in Epi-Jomon society (ca. 400 BC – AD 700), and also highlight the importance of re-examining old skeletal collections where evidence of violence may have been overlooked in the past.

Key words
Perimortem injuries, blunt force trauma, projectile trauma, Epi-Jomon culture, Japanese prehistory