Ive seen several pots like this. When you say "glass" I assume you mean Outlined glaze? When you look closely, is there a thin layer of black separating the blue from the unglazed portions?
I've seen many 1st and 2nd gen Tosui like this, in blue over unglazed clay. The technique is more common with multicolor yellows from Kyoto, dragon pots mostly. I dont recognize the chop, and it's not in my database, I would say Chinese.
The blue is still shiny and very bright, odds are it's not real old. This is merely an assumption based on patina, since I dont know the maker, it could be a shelf pot! About 15% of the verifiably old Chinese pots I see don't show their age, but they're generally more ornate, higher quality.
Shoot me an email and Ill send you photos of very similar pots and biblio, I only have an IPhone, so I cannot post pictures here http://japanesepots.wordpress.com/ Gastrognome@aol.com