Metro Token - Nanjing 南京地铁；Jiangsu

There many varieties.
There is a test token. On Reverse “AFC” can found:
 

Beside the test token there are three main varieties with several subvariations.

The three main varieties can be distinguished by suffix of serial number.
The suffix of the serial number can be found on reverse and is "FS", "FC", of "FY".
The tokens with suffix "FS" are dark blue, with "FC" blue, and with "FY" grey blue:

The main varieties differ also in the stylized "M" in the plum blossom logo and the thickness of the obverse border:
- FS: stylized M is edgy, thinest border
- FC: stylized M has rounded edges, middle thickness of border
- FY: stylized M has rounded edges, thickest border

The subvarieties are seen on reverse.

Subvarieties of "FS" tokens:
- no chinese lettering (There are also differences in font)

- two lines of chinese lettering (There are also differences in font)

- three lines of chinese lettering

Subvarieties of "FC" tokens:
- two lines of chinese lettering

- three lines of chines lettering

Subvarieties of "FY" tokens:
- blank reverse

- two lines of chinese lettering (There are also differences in font)

2020 onwards tokens with dark grey reverse appeared and a new suffix "FD". The token with suffix "FD" has an obverse similar to the "FS" tokens.
Subvarieites with dark grey reverse:

- “FS” suffix, no chinese lettering

- "FS" suffix, two lines of chinese lettering

- "FD" suffix, two lines of chines lettering