http://www.calgarycoin.com/reference/china/china8.htm#yung cheng
Don.....
PS: To be clear, I am not the expert.
I have used this website to identify several Chinese coins.
Trick is, to Orient (pun not intended) the coin, so it matches
the drawings or photos. Dynasty may be a big chunk of time,
but you will get within the ballpark, of how old it is...!
Great Find...!
Chinese Coins
Mackaydon has it right, as it shows the variety that the Reverse of the coin has - as it would give you more info of where it was made - within 8 years, in the case with this Emperor anyway...!
Very old coin...! Perhaps an heirloom of family, and personally valuable, and worn on the clothing............