Unknown cash coin

Vladimir Belyaev
November 25, 1999

be long, a long time be calm, peaceful Current Treasure
Jiu An Tong Bao
The Current Treasure of the Longterm Peace

Reverse: plain

Diameter: 24.9 mm
Weight: 5.2 g

I found only one reference on this coin in the Ding Fu Pao book (#3109) in the section of unattributed coins:

Message from Howard A.Daniel III (25-Nov-99):
          This coin has a very Vietnamese appearance to me. The "Long Peace" would fit in with several eras in Viet Nam. The metal also looks like of Central or Southern composition.

Message from Sergei Shevtcov (26-Nov-99):
          I checked my references. In one source coin mentioned as Japanese without any comments, price 100 silver yuan (in prices of 30-40s). Ding Fu Pao - undefined coin also priced at 100 silver yuan. Not recent China source - 6000 RMB.
          I think that it is Japanese coin, because first character Jiu has never used at Chinese cash coins legends, but known at Japanese ones. Calligraphy style is very nice and patina seems to be genuine.

Message from Gilbert Tan (26-Nov-99):
          It is a forgery of the Ding Fu Bao piece. The appearance to me is very suspicious, commonly seen on fake coins.

Message from Wei Dong Zhang (29-Nov-99):
          Now most Chinese scholar believe Jiu An Tong Bao is a Vietnamese coin. It is very rare and quite expensive in Chinese market.
          But the one you show us here looks like a fake: the patina is not good,and it should not red copper,but bronze (according to the photo).

Message from Wybrand Op den Velde (02-Dec-99):
          Coole 'Coins in Chinese History' (1967) gives only five references. In his unpublished book on cash coins W.D. Smith has listed it as a Japanese issue, dated 1145-1151 (however, without reference). The origin, place and date of production are simply unknown. Some authorities believe it is Japanese, others that it is Vietnamese.
          Your specimen looks somewhat suspicious. I have one such coin, bought recently on a market in Xian (PRC), which is probably a recent forgery:

Any additional information highly appreciated.
Chinese Coinage Web Site