Vietnam coin bears Chinese Song Dynasty reign - Zhi Dao Yuan Bao
This piece of coin is found in java, Indonesia. It coincident with a Chinese Song Dynasty Zhi Dao Yuan Bao. This type of coin is believed to be either produced by ancient Vietnam or in Java, Indonesia. 22.9mm/ 3.27 VF - Price 4 USD @ dong_hua_zhai's Coins and Antiques
Note : In ancient, Merchants from China, Vietnam, Japan and Ryukyu islands use huge junks to bring in cash coins in exchange of spices and rice with Javanese people.