China, County of Yan, Knife Money Yuanbei Mingdao

In the County of Yan, knife coins were introduced during the 7th century BC. The currency and weigh unit of these coins was "huo," a character meaning "barter" or "trade." Knife coins must have circulated in a huge area. Thousands of them were found from the North Hebei to Inner Mongolia, and across the Liaoning Province to Korea; single finds have even been made in Japan.