Vintage Cast Iron Black Japanese TEAPOT with Hobnail design. This possibly could be Tetsubin(?) but not sure as there are no markings in English. There is Japanese writing characters on the bottom. It has a carrying handle. The inside of the teapot and the underside of the lid are glazed.
Teapot measures 6" from spout to back x 5 1/2" from side to side. Stands 3-3/4" high to the top of the lid. Very heavy.
The teapot needs a good cleaning and shining. There are scuffs, scratches and finish loss as well as light rust along the bottom edge and along the top edge under the lid.
It has a nice patina. Very beautiful even if you use it for display only but is still useful as a teapot!