Ito Chisels

Japanese chisels (nomonomi) use a laminated construction where a hard layer of high-carbon steel (hagane) is forge-welded to a softer iron body (jigane), whereas most Western chisels are made from a single uniform steel alloy. This lamination allows the cutting edge to be hardened to a higher Rockwell hardness—often HRC 62 or above—while the softer iron back absorbs mallet strikes without shattering.

Yes, Japanese chisels should be sharpened exclusively on water stones, never on oil stones or powered grinders, because the high-hardness laminated steel is sensitive to overheating. The hollow-ground back (urasuki) must also be maintained carefully—flattening only the flat perimeter edge so the hollow recess is preserved for reduced friction during paring.

No, Japanese chisels are designed to be struck with a wooden mallet, typically made from Japanese white oak (kashi), not a metal hammer. The hooped wooden handle is engineered to absorb mallet strikes, and using a metal hammer can split the handle or damage the forged hoop.

The cutting layer of quality Japanese chisels is commonly made from Shirogami (White Paper Steel) or Aogami (Blue Paper Steel), both of which are hitachi carbon steels prized for edge retention and sharpness. Shirogami takes a keener edge but is more prone to chipping, while Aogami contains tungsten and chromium additions for slightly better durability.