July 12, 1998
Diameter: 78 mm|
Obverse: Cho Nen Dai Ho (Chang Ta Nian Bao in Chinese)
At the obverse placed legend of Japanese coin issued in 848 AD. But real coin
has size 20-21.5 mm (look quotation below).
Image received from Jim Farr.
Abridged history of the copper coins of Japan by Leon van de Polder, 1891 (from The East Asia Journal, 7, 1982):
Two different kinds were made, viz.:
1st had a diameter of over 6 bu or 18.5 mm and weighed over 5 fun or 29.15 grs.troy.
2nd had a diameter of over 6.5 bu or 20 mm and weighed 4 fun or 23.32 grs.troy, but it seems that some were minted having a diameter of 7 bu or 21.5 mm and weighing 8 fun or 46.64 grs.troy.
Chinese Coinage Web Site