As it is known in a Japanese folktale called "Bunbuku chagama" (The Magic Teakettle), chagama is made mainly of iron and comes in various sizes from 30cm to around 100cm in diameter.
分福茶釜で知られるように茶釜は小さなものは直径30cm程度から、大きなものは100cm程度まであり、主に鉄で作られている。