I have attached some pictures and would like to ask some questions. I just got this piece and is confused to determine between new or old and fine or copy.
It is a small stem cup which is 3,75 inches high, this is the finest one I have ever seen, it has in blue underglaze characters a Ming Cheng Hua period mark. It is finely painted with birds and flowers on the body. I have looked carefully and the glaze is full of bubbles.
Is glaze with bubbles typical of "Ming" glaze? Would you give me your opinion about this cup.
This "Chenghua" vine cup is I believe a very recent fake. It is not Chenghua anyway. I am pretty sure about that since I have had the pleasure of studying a few real ones, excavated at the site of the Imperial Porcelain Factory in Jingdezhen.
I also think the mark is too good for this to be a 19th century copy.
Pieces of this quality could have been made during the Daoguang period, but I don't think this one is that early.
Regarding "bubbles in the glaze" it is sometimes of importance but I have not studied any pieces that carfully to know how to explain what to look for and when. I would advise against using that as a rule for anything.
Please note that this is only an advise based on seeing a picture only. The final decision is up to you but "good" fakes are selling in Shanghai at 30-40 US$ so don't pay too much :-)