XINZUO Sharp And Durable Santoku Knife 440C Steel Core Hardness 60±1HRCFrequently Asked Questions Q: What type of steel is used in this knife? A: The blade features 3 layer composite steel construction a hard central layer sandwiched between softer outer layers. This design provides excellent sharpness and edge retention while making the knife easier to sharpen when needed. Q: How hard is the blade? A: The core hardness is rated at 601 HRC, achieved through precise heat treatment. This level of hardness ensures the blade