The shape is unusual and it looks very old. That's all I know. I need some help to identify this. Thanks
Looks indeed old, but I never saw a Chinese shaped bottle like this. The foot and neck are usually shorter.
If the neck and foot were shorter, how old would you estimate its age? Could it be japanese or vietnamese? Or a rare chinese shape?
Difficult to tell. I have not seen enough Vietnamese items, the Japanese would have copied anything, perhaps, but I doubt this is from there. Korean might be an option, perhaps.
I agree with Peterp,
This could be Korean. The crackle glaze looks from the Joseon dynasty, but the shape... I have never seen something like this in my few knowledge of Koran ceramics.
The neck and mouth look like those of some Korean items, but I'm not sure about the base. I do not really know if it could be a Korean foot rim, but the item is old, apparently.