Before revision: By country Japanese katana 350px Forging Tamahagane Japanese smiths discovered, similarly to many others, that iron sand (with little to no sulfur and phosphorus) heated together with coal (carbon) made the steel they called tamahagane.
After revision: By country Japan 350px Forging Tamahagane Japanese smiths discovered, similarly to many others, that iron sand (with little to no sulfur and phosphorus) heated together with coal (carbon) made the steel they called tamahagane.