A 2mm thick "Shiro 2" white carbon steel core (C 0.95-1.0, Cr 0.2-0.5, Ni 0.7-1.3) with 11 alternating layers of soft and hard steel on either side. The inclusion of Nickel and Chromium in the core layer broaden the temperature range in which a Martensitic structure is produced after quenching. This makes it easier to produce a really good blade when hand forging.
To maintain the purity of the steel and minimise carbon diffusion use a charcoal forge if possible. Forge at 800°- 900°C. After forging and grinding, cycle at 750° - 800° to release any tension from the forging process, harden at 800°C and quench in oil (ie: vegetable) recommended or lukewarm 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° to relieve the hardness to between RC62 and RC59 respectively.
330mm x 33mm x 5.5mm Unhardened Billet
