I have had this dish for years with my bonsai collection though I have never planted anything in it, except to exhibit a minature orchid once in awhile. I have placed an inquiry on your ads page, but then I saw where I could send an email and ask for some help identifying this.
If you would view the pictures of the dish and let me know if it has any true age. I have always been fascinated by the circular pads on the bottom of the legs and the circular discoloration in the center of the clay bottom, flanked by rectangular discolorations on either side.
I have enjoyed your site so much and have gone over it again and again trying to identify some chinese pewter bowls and an old japanese wooden bowl I have. The history you give is fascinating. I had no idea. Thank you so much for sharing your knowledge with all of us.
Thank you for sharing your nice Bonsai pot with me. Unfortunately I do not recognize it as a Chinese antique pot. It could be up to a hundred years old, anyway. From its decoration and general "feel" it could very well be Chinese, but there are many pieces that could have been made in either country. This is one of them.
What leads me to believe this might be a Japansese piece, are the unglazed spots under the pot you specifically mention. Such unglazed spots usually indicates it has stood on some kind of support - either when the glaze was applied - or under the firing, when the clay actually melts and become so hot that it glows.
During this, especially Japanese clays have a tendency to lose shape. I therefore find it likely that your pot is Japanese and probably from the mid 20th century.
Please note that this is in no way a "final verdict" on your nice pot, but only as far as I get :-)