Our handmade Yoshihiro Aonamiuchi Blue Steel knives are crafted with extraordinary skill by our master artisans. Aoko Blue Steel #1 with a hardness on the Rockwell scale of 63 to 64, is intricately forged with iron to create beautiful wave like patterns. It takes a very high degree of skill to create knives of exceptional performance with such exquisite beauty. Namiuchi means wave forged, and our master artisans blend aesthetics with the highest quality materials and craftsmanship.