That process was to hit the fold process hit the fold will make the structure of steel details. Carbon is the same element of every position. Thus making the swords have a backpack naphon strength.
The interest is to hit the strike fold fold. Will help make the structure of the steel profile. The distribution of carbon equal position. It just makes a stronger sword.
Process for interested is hit fold, the process hit fold will help to make the structure of the steel detail. Dispersion of carbon rate every position. Is the sword is strong.