Shapes of Meiping (in Chinese)

[peterp]

Here is an online article about the different Meiping shapes through the ages. It is in Chinese...you will need to use an online translator application if you want to read it.
Link:  kknews.cc/zh-tw/n/b384epj.html

On the left, just above each group of Meiping the era is given in which these were used. Sometimes the shape helps with dating.
Here are the periods of each group in English from top down:

Sui, Tang
Northern Song
Liao (empire)
Jin dynasty
Western Xia (empire)
Southern Song
Yuan dynasty
Ming dynasty
Qing dynasty