Iron Kettle Metal Craft Sencha Tea Utensils Antique Item With Signature: Nanbu? Yoshi. Tea Ceremony Ironware

This is an antique iron kettle. It appears to have been left outside for many years and is heavily rusted. There seems to be a maker's mark, but it is illegible. Is it Nanbu? Yoshi? The lid has a cute knob that resembles a pinecone. It feels surprisingly heavy for its appearance. I observed it for three days, and there seem to be no water leaks.

Product Details:
Dimensions (approx.): 20 x 20 x 20 cm (width x depth x height to handle)
Height to rim: 11 cm
Rim diameter: 90 mm
Weight (approx.): 2.6 kg