Blue Steel No.1 (Hitachi Metals Ltd.) is very similar to Blue Steel No.2, but the additional Carbon and Tungsten / Wolfram result in even better edge retention and toughness. The steel is perhaps most commonly seen in high-grade Japanese traditional single-bevel edged knives.

C 1.25- 1.35 % | Cr 0.3-0.5 % | W 1.5-2.0 %