Daisuke's Kurouchi Black-finished (Kurouchi) blades are made with an inner core of Yasuki's traditional Hagane --- Shiroko / White Paper No.1 Hard Steel,which has been widely used for a very long time in Japan --- supportedly by a layer of softer persistent steel for an exceptionally sharp and smooth cutting experience.
Of particular note is that he definitely applies "Warikomi" process to make any blade. The Warikomi is an ancient Japanese manufacturing process, (1)split the heated soft steel with a wedge, (2)insert the hagane steel into the soft steel bar, (3)hammer the merged steel bar to form it into a three-layered construction of steel sandwiched by the soft steel.
You can grind it to extreme sharpness, which it retains for a long time. The edge is particularly suitable for the gentle preparation of foods though you need to treat the blade to prevent from rust.
