Why did my Japanese knife chip or go dull, and how do I fix it?

Chips almost always come from hard contact: bone, frozen food, a ceramic plate, or the edge knocking the sink or a glass board. Rapid dulling usually means either normal wear or an edge that was sharpened at too steep or inconsistent an angle and never fully refined.

To fix a chip, grind the edge down on a coarse stone until the chip is gone along the whole edge, then work back up through the grits to restore a clean, even bevel. It removes a little steel, but a chipped edge only gets worse if you ignore it.

Our K&S take: a 400 grit (for example within a Naniwa Chosera 400/1000/3000 ladder) does the heavy repair, then the 1000 and higher refine. Keep the stone flat with an Atoma plate so the repaired edge stays true.