many fake Panda coins are offered at Ebay. besides the weight which you can check after receipt of coins there is another easier way to tell real from nearly all copies: the real ones show the denomination, e.g. 5 Yuan on the avers, somewhere near the panda. the copies just show the Panda + some phantasie text in Chinese. Copying the "5 Yuan" carries death penalty so nobody dares to do. many copies come with nice "certificates of state bank" which are forged too...