Kohetsu is a name that loosely translates to "bring happiness and pleasure" or just "be happy." Kohetsu knives are about bringing you the best cutting performance using the top steels on the market with impeccable heat treatment and nice, thin grinds at an affordable price. SLD steel by Hitachi is hard, tough, and strong against wearing. Hitachi has improved it for better work and longer life, and named it SLD. The HRC after heat-treating reaches about 61-62.