Great teapot, but it's not a Tetsubin.
This little cast iron teapot is more appropriately called an "iron kyushu" or "iron teapot". Because of the enamel glaze, the iron does not really react with the tea to create the classic tetsubin "richness", and the teapot cannot be used to boil water. That being said, it is an excellent, sturdy and convenient vessel for brewing tea, especially with the strainer basket included. It's a great little teapot, and the thing appears like it will last forever if taken care of properly. It warms evenly and quickly and stays warm for a long time. My only other observation is that the little cups, being iron themselves, get hotter than the tea itself, it seems. I've found them impractical for use, as the heat retention is excellent and the cups just remain too hot to pick up comfortably. If you're looking for a solid, practically-sized teapot for brewing and serving that you can pass down to other generations, this is a good choice. If you're looking for a real tetsubin that you can boil water in, etc., look elsewhere.