Sharpening a Japanese knife is not simply a matter of grinding steel — it is an art form shaped by centuries of craftsmanship. Before touching a whetstone, chefs must understand the principles that preserve both performance and longevity.

On single-edged knives, the urasuki hollow on the back is essential for reducing resistance and maintaining sharpness. Over-sharpening the back can thicken it and dull the blade, while too much pressure risks distortion that only professionals can repair.

Sharpness itself must be balanced with purpose. Knives like Deba or Garasaki, which face hard materials, can chip if made overly thin. The ideal edge is one suited to the task, not always the thinnest possible.

During sharpening, the formation of a burr (kaeri) signals progress, but excessive burrs mean wasted steel. Likewise, the mud produced by whetstones can enhance polishing, yet too much can reduce control. Skilled sharpeners know when to keep it, and when to rinse it away.

Sharpening is not just maintenance — it is an act of judgment, discipline, and respect. By following these principles, a knife’s edge becomes not only sharp, but truly suited to its purpose and to the hand that guides it.