Smelting Tamahagane

• 1). Smelters construct a traditional Japanese furnace known as a Tatara. To make a Tatara, place bellows underneath clay walls approximately one meter thick, one meter high and three meters long.
  
  
• 2). Ignite an open flame in the Tatara, fueled by charcoal and the bellows. Once the flame is hot enough for the smelter, iron powder is placed into the Tatara. The temperature can vary depending on the kind of iron powder and the prerogative of the smelter.
  
  
• 3). Put out the fire and tear down the walls of the Tatara after the iron sand and the charcoal melt together, usually this takes about 48 hours. The result is a molten kind of steel known as Tamahagane.
  
  Pieces of the Tamahagane that contain 1 percent to 1.5 percent carbon content are used in the production of samurai swords. Experienced smelters can tell the carbon content by sight, but a laboratory chemical analysis can achieve the same result.
  
  

Refining and Forging

• 1). One person holds a piece of the Tamahagane with tongs while two others flatten and break it into small thin pieces with large hammers.
  
  
• 2). The pieces are wrapped in paper and covered in clay and ash before being put into a furnace, where they are welded into one piece.
  
  
• 3). While the new flat and larger piece of Tamahagane is still hot, the person with the tongs holds the piece and has the people with the hammers flatten and straighten the new piece until it becomes a block.
  
  
• 4). The block is then placed back into the forge until it is hot enough to bend. Once the block is hot enough, it is folded and then hammered flat again.
  
  This process is repeated until all impurities are removed from the block, which can be seen when the block is nearly white coming out of the fire.
  
  
• 5). Several of the refined Tamahagane blocks are forged together into a thin rod. This rod is then placed in the middle of a sheath of higher carbon metal known as habe-gane and covered in a clay and charcoal coating known as the hamon.
  
  The sheath and the rod are fused together until red hot and then placed into a pool of water, where the clay cracks away and the newly-formed sword bends slightly.
  
  

Polishing and Sharpening

• 1). The lower edge of the blade is initially sharpened and the blade is cleaned.
  
  
• 2). Now the bottom of the blade is ground along coarse grinding stones and the face is ground along slick polishing stones to make the sword smoother and sharper.
  
  
• 3). Finally, small mud like particulates known as hazuya stone are placed along and inconsistent parts of the blade and those parts are ground down specifically.