RMB. The Yen is Japan. RMB is China or if you dumb like me when i went you could change all your currency into Hong Kong dollars and have to pay to change it back but hey ho...
I was there 10 years or so ago. When you changed your money into Chinease currency you got rather nice new notes which our tour guide called RMB. At the time we were told only to spend them in authorised shops. However, if you spent the RMB at the local shops / markets you got a much better deal. You just had to make sure that you got your change back in RMB and not Yuan or the seller ended up getting the best deal. The local Yuan looked like it had been in circulation for years and was absolutely manky! You also needed to really enjoy hangling for a good buy. It could take a while.