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. The appearance to me is very suspicious, commonly seen on fake coins. It is very rare and quite expensive in Chinese market. 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.