The dual-core blade of the Shun Nagare series is produced by kai using an innovative forging process. Two types of steel with different properties are combined to form a 72-layer Damascus blade. The combination of a flexible, resistant VG 2 steel and a particularly hard VG 10 steel results in a hardness of 61 (±1) HRC. As a result, the blades, which are ground on both sides, have particularly long-lasting edge retention and excellent sharpness.