A 1mm Hitachi Ao Gami blue paper steel core with 1.25mm unalloyed iron cheeks laminated on either side.
To maintain the purity of the steel and minimise carbon diffusion use a charcoal forge if possible. Forge at 800-900 Celsius, forge weld at 1100 Celsius using borax to flux the surfaces. After forging and grinding, cycle at 770 Celsius to relieve the mechanical tension built up in the forging process and cool slowly. Harden at 800 Celsius and quench immediately in oil or water for 20 seconds, remove from the quench and allow to finish cooling more slowly, dabbing the back of the blade on a balled up wet rag.
Temper at between 150 and 250 Celsius to relieve the hardness to between RC64 and RC59 respectively.
350mm x 33mm x 3.5mm Unhardened Billet