Here is a picture of  three pots, all with the same chop as above. The largest pot size is  12x8x3

Thank you for the help, I looked at your resource page, as well as some other sites, but i missed the Tokoname Bonsai Pot Makers site, as well as your blog. Much easier to find this information looking backwards!

Here is a picture of the smaller pot 190x140x44mm. So I assume it is a production pot. Any idea of the age? The clay looks different than what is currently offered.

Thanks, also a test of my camera.