Baijin Sanpin is a set of three types of coins: Dragon, Horse and Turtle issued in the Han dynasty 119 BCE.
"Bai Jin" refers to the metal, lead, "San Pin" refers to the fact that it was a series of three coins with different denominations. Dragon, Horse and Turtle.
The Dragon Coin:
A lead coin worth 3000 Wu Zhu coins.
Issued bu Emperor Wu Di of
the Western Han dynasty - presumably to strengthen trade with
the Greco-Bactria state since the script is not Chinese
but Bactrian.
The territory of Bactria was called
大夏
Dàxià
in Chinese
(read about Bactria on Wikipedia).
The obverse image is a dragon.
The reverse legend is in Greek characters! There has been many attempts to decifer the
meaning but it
seems it doesn't make sense in any way.
The large images of the Dragon coin and the clay imitation are my own, the other images are not.
A clay imitation of the Dragon Coin.