Making a Masterpiece
Smelting steel
The traditional katana sword is fashioned only from the purest
steel, which the Japanese call tamahagane ("jewel steel").
Over three days and three nights, smelters using ancient techniques
shovel roughly 25 tons of iron-bearing river sand and charcoal into
the mouth of a tatara, a rectangular clay furnace built
specifically to produce a single batch of tamahagane. Composed of
carbon, the charcoal is as much a key ingredient in steel as a
source of fuel for the furnace. The tatara will reach temperatures
of up to 2,500°F, reducing the iron ore to steel and yielding
about two tons of tamahagane. The highest quality tamahagane can
cost up to 50 times more than ordinary steel made using modern
methods.