Knife Sharpening
A sharp knife is safer than a dull one. With a sharp edge, the blade goes where you direct it. With a dull edge, you push harder, the knife slips, and the cut happens somewhere unintended. Sharpness isn’t about the knife — it’s about control.
Sharpening restores the edge geometry that use degrades. Every cut rolls the edge slightly, bends micro-teeth, removes steel. Kitchen knives need maintenance monthly or weekly depending on use. The goal isn’t to make the knife sharper than factory — it’s to maintain sharpness consistently.
Edge geometry determines performance. The primary bevel is the main angle ground into the blade, typically 15-25 degrees per side. Lower angles cut more easily but dull faster. Higher angles resist damage but require more force. Kitchen knives average 15-17 degrees per side; outdoor knives run 20-25.
Japanese knives often use asymmetric grinds: 70/30 or even single-bevel designs. The asymmetry creates a steering effect — the blade pulls toward the steeper side. Single-bevel knives for sushi require specific sharpening technique to maintain geometry.
The micro-bevel is a slightly steeper angle at the very edge, adding durability without changing cutting feel. Many sharpeners finish with a micro-bevel: maintain 15-degree primary, then take a few strokes at 20 degrees. The compromise gives both keenness and edge retention.
Whetstones are abrasive surfaces rated by grit — the particle size of the cutting material. Lower numbers cut faster but leave rougher edges:
120-400 grit: Coarse. For repair work, major reprofile, chip removal. Skip unless the edge is damaged. 800-1200 grit: Medium. For regular maintenance, establishing the edge. 3000-6000 grit: Fine. For polishing, refinement, final edge. 8000+: Extra fine. Diminishing returns for most users; relevant for razors and single-bevel Japanese knives.
A two-stone progression (1000 and 6000) handles most kitchen knife maintenance. Start coarser only if the edge is damaged or the angle needs changing.
The technique matters more than the stone quality. Soak water stones 10-15 minutes before use. Create a slurry with a nagura stone or the sharpening stone itself — the slurry contains loose abrasive that accelerates cutting.
Maintain consistent angle throughout the stroke. Most beginners lift the spine too high and round the bevel. A useful heuristic: imagine the knife edge is trying to shave a thin layer off the stone. Angle too steep and you’re scraping; too shallow and you’re just sliding.
Apply pressure on the forward stroke (edge leading), lighter on the return. Work sections of the blade rather than trying to sharpen the entire edge at once. Heel to belly, belly to tip, alternating sides to maintain symmetry.
The burr is how you know sharpening is working. As you grind one side, steel rolls over the edge creating a thin wire (the burr). Run your finger from the spine toward the edge — you’ll feel the burr catch. When you have a consistent burr along the entire edge, switch sides.
Alternate sides with decreasing pressure until the burr breaks off. Then strop on leather or denim — a few light passes to align the micro-edge. Test on paper or tomato skin. The knife should cut without requiring pressure.
Japanese knives (wa-bocho) require more attention than German (westernized) knives. The harder steel holds edges longer but chips more easily. The thinner geometry means less material to remove but less margin for error. Single-bevel knives need specialized technique — only sharpen the beveled side, then very light work on the back to remove the burr.
The difference reflects sharpening philosophy: the German knife is robust and forgiving; the Japanese knife rewards careful maintenance with superior cutting performance. Neither is better — they’re different relationships between tool and user.
Sharpening is meditation disguised as maintenance. The rhythm of stone and steel, the focus on angle and pressure, the immediate feedback of an edge that works. Like all craft maintenance, it’s not separate from the work — it’s the foundation that makes good work possible.
Go Deeper
Books
- An Edge in the Kitchen by Chad Ward — Comprehensive treatment of knife selection and sharpening. Practical and well-organized.
- Japanese Woodworking Tools by Toshio Odate — The sharpening section applies beyond planes and chisels.
Videos
- Murray Carter’s knife sharpening tutorials — Carter trained in Japan for 18 years; his technique instruction is rigorous.
- Jon Broida / Japanese Knife Imports — Excellent demonstrations of single-bevel technique.
Related: sharpening, tools, craft, maintenance, shokunin