A 1mm Hitachi Shiro Gami White 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 750 Celsius to release any tension from the forging process, harden at 775 Celsius and quench in warm water (850 Celsius for oil) and temper at 200 Celsius.
350mm x 33mm x 3.5mm Unhardened Billet