The raw materials for tamahagane are iron ore (satetsu) in the form of sand and charcoal. Satetsu was extracted from the sand in the riverbed in the Edo period.
Satetsu is extracted from the sand in the riverbed, and in the Edo period, the sand was washed through a waterway with wooden bars, and the iron sand was separated by leaving the heavier iron sand in place and the lighter sand washed away by the water.