Other than Tamahagane, pig iron (Sentetsu) which contains a lot of carbon, and pure iron called Hocho tetsu also undergo Tsumi wakashi and Shita-gitae processing mentioned below.
玉鋼以外に炭素量の多い銑鉄と包丁鉄と呼ばれる純鉄も積沸かしと次の下鍛えの作業を行なう。