Cast iron teapots were believed to have been first used in Japan in the 17th century. These teapots were called "Tetsubins" and gained popularity with the affordability of Sencha, a Japanese green tea. The cast iron tea sets of today have an enamel coating on the inside to prevent rusting and for ease of care, as well as having a decorative exterior design that showcases the ware outside the kitchen. This also means that the tea ware does not absorb the taste of the tea, unlike yi xing clay pots which become seasoned from use. The cast-iron also keeps tea warm much longer than other materials, which is great if you want to linger over a pot of tea throughout the morning and for generations to come.