Nguen Att is the smallest change.   100 att= 1 kip
Nguen Hang is real silver look like a litle boad, used as currency 
in 1800 something. After French took over our country,they changed from real silver currency to the Bronz coin currency
and they changed it again to the paper currency later;called
Indochina currency. that's all the info. i have, hopefuly someone
(Granpa) can comes up with more and better info.
                                               Thanks