This was a legendary steel way ahead of its time and stronger than any other while also having small amounts of flexibility and good edge retention. It was made by gathering satetsu sand and iron and smelting them in a large clay furnace for 72 hours. when the clay is finally cracked open you have Tamahagene steel ready for the forge. The steel chunks are sorted into three categories based on strength and hardness hard medium and soft this is determined by the sound they make when banged on something. The steel that is hardest is folded and hammered into a rough thin sword shape. This makes the core of the sword then the softest steel is folded over on top of the hard creating the second layer. Then the medium is folded on that and then the hard is folded on top of that this is the only layer you will be able to see the hard on the outside gives it a strong durable cutting edge while the soft inner layers allow it to sometimes flex to avoid shattering.this is one of the most common layering techinqes but there are many others.
For more info check out this video http://www.youtube.com/watch?v=Tbnc1KKQdHk
