This is a Nambu ironware pot from Nanbu Seieido. I believe it's a sukiyaki pot, but it doesn't have a handle. It was rusty, so I polished it, heated it, and then applied oil. Inner diameter: 19.8cm (top), 19cm (bottom), outer width including handles: 25.5cm, depth: approximately 4.5cm. The box says it can be used with an IH cooking heater. The box is quite damaged.