China-empire coins

I am looking at a couple of Qianlong 1 cash coins.  I believe I have narrowed them down to these two: https://en.numista.com/catalogue/pieces1133.html & https://en.numista.com/catalogue/pieces19755.html

question 1: What is the FD# ?  Shouldn't there be a Y#
question 2: What is the DH# ? Shouldn't these also be Y#'s

I would like to give the appropriate Catalog # for my coins.

Thanks!

Yeoman (Y#) never issued a catalogue for old cast coinage, but World Coins (KM#) did. The reason why we do not use KM#s is because they are extremely inaccurate, listing coins that never existed.

FD#s (Fischer Ding) and DH#s (David Hartill) provide coin types and varieties, respectively. While FD#s are organized like Y# and KM#, listing coins with different inscriptions separately, DH#s do a good job listing all varieties of Chinese coins.

I hope this clears things up.

It does very much.  Thank you.