I have a Chinese Yizing Zisha Clay Fish Teapot with a Frog as the Lid

[vsw2020]

I would like to know what this backstamp states if possible or where to go look for it.  Many thanks!

[peterp]

This is from the main site: https://www.chinese-antique-porcelain.com/yixing-pottery.html

It is difficult to estimate the age of Yixing wares as they show no clear age signs, unlike other ceramics (Yixing wares are considered 'stoneware' in the West). The marks themselves are also not using the usual character styles found on porcelain, rather those found on seals, and the authenticity of master craftsmen/-women is difficult to verify. There are lots of fakes of the marks of well-known teapot craftsmen. Usually, only those specialized in those teawares are capable to recognize fakes and fake marks. Most Yixing collector's items are less than 70 years old anyway. Qing dynasty Yixing teapots were often not marked.

For more information, just make an image search for "Yixing teapot marks" and follow the links. The only source for zisha marks I have seen online  was in Chinese. It seems to have been published by Yixing town.