Iron Ingots
Japan’s early relations with the Korean Peninsula and the Asian continent were crucial for keeping up to date with the latest technological developments. Many valuable commodities such as silk and tea and ideas like Chinese script and Buddhism, arrived by sea. These flat iron ingots discovered at a fifth-century ritual site on Okinoshima, testify to the importance of iron in ancient Japan.
It is thought that the Yamato court (300–710) imported iron from the Korean Peninsula, and protecting this important resource may have been behind their decision to send Japanese troops to the region to support their allies. Refugees from the Gaya region of Korea, an area known for its iron foundries, were employed by the Yamato court to craft horse trappings and armor, which, according to some researchers, gave them an edge in battles for hegemony within Japan.