It may also refer to this, going back 4000 years: https://en.wikipedia.org/wiki/Bloomery#Sub-Saharan_Africa https://en.wikipedia.org/wiki/Bloomery#Sub-Saharan_

It may also refer to this, going back 4000 years: https://en.wikipedia.org/wiki/Bloomery#Sub-Saharan_Africa https://en.wikipedia.org/wiki/Bloomery#Sub-Saharan_Africa More in https://en.wikipedia.org/wiki/Iron_metallurgy_in_Africa https://en.wikipedia.org/wiki/Iron_metallurgy_in_Africa They mention inhomogenous steel there though, it sounds like the Tanzanian one was more purely directed at making steel instead of iron.