What is Tamahagane Steel?

What is Tamahagane Steel?

Tamahagane is a steel originating from Japan which often used to create traditional Japanese swords. In a metallurgical sense, the metal is primarily made up of two parts, steel ore, and carbon. The steel ore originates from iron sand and the carbon is derived from charcoal. These two components are heated and smelted in a traditional bloomery, which is also known as the Tatara. Once this mix is sufficiently heated the two components are melted into a steel slag called Tamahagane.

Japanese Iron Sand


The process used to create Tamahagane is quite labor intensive and it’s carefully regulated and supervised by the NBTHK (Nittoho) organization. Only steel made in the traditional manner and in an authentic Tatara (which there is only a handful left in the country) can be called tamahagane. The NBTHK also control the sale and regulate the distribution of iron sand ore sand, ensuring all resulting steel meets their strict guidelines.

A ‘Nittoho Tatara’ is only allowed to be lit for a three week period in the deepest part of winter, this ensures the humidity is at its lowest which creates a purer steel. During this three week period of activity, each forge can create a maximum of three batches of steel, with each batch taking 7 days to process and complete.


Due to the very limited and regulated supply of Tamahagane, prices are extremely high and competition between sword smiths to acquire the steel is fierce. Due to this limited supply of traditional steel, many smiths will use a steel blend called orishigane (leftovers). These leftovers can be made up from old nails, steel shavings and other types of iron-containing materials. By supplementing the steel with additional charcoal, the swordsmiths are able to control the amount of carbon present in the resulting Oroshigane steel ore. Most traditional swordsmiths will use smaller versions of the Tatara, which are often bespoke made by the swordsmiths themselves.

Due to the heavy regulation imposed on Tamahagane production by both the government and the NBTHK corporation, it’s very unlikely that any swordsmiths that are not registered will be able to acquire Nittoho Tamahagane.

Anyone that is located outside of Japan is free to create their own Tatara and smelt tamahagane. However, the traditional iron sand (ore) that is used in the production of Nittoho tamahane is only found in the Northern tip of Japan. The sand (satetsu) is unique in terms of chemical makeup and color (green / brown), and it’s these impurities that give Tamahagane it’s unique visual feel and looks. So, even if you have your own forge up and running, you’ll not be able to replicate the coloration and features present in genuine Tamagane without access to the genuine iron ore sand.