HAP40 Core Steel Japanese Knives

HAP40 is a high-performance steel used in premium Japanese knives, prized for its exceptional edge retention and hardness. Made by Hitachi, it’s a powdered metallurgy tool steel alloyed with high levels of tungsten, molybdenum, vanadium, and cobalt. HAP40 can be hardened to 65–68 HRC, allowing it to hold a razor-sharp edge far longer than most conventional steels.

Despite its hardness, it’s relatively tough and resistant to chipping. It’s semi-stainless, so it resists rust better than carbon steels but still benefits from proper care. Sharpening requires more effort than softer steels, but the fine, long-lasting edge is well worth it.