Why Japanese Knives Are Sharpened on One Side Only
The blade bites through fish like water.
When you watch a sushi chef work, the knife doesn't saw or press—it glides. One clean motion, and the flesh parts without tearing, without bruising the grain. The secret isn't just sharpness. It's geometry.
Most Western knives are ground symmetrically, sharpened evenly on both sides. Japanese single-bevel knives—like the yanagiba used for slicing sashimi—are sharpened on one side only. The other side stays flat, sometimes even slightly concave.
This asymmetry isn't an accident. It's inherited from the forging techniques of Japanese swords, where differential hardening and beveling created blades that could hold an edge and flex without breaking. But in the kitchen, that single bevel does something else entirely: it controls the direction of the cut with near-surgical precision.
The flat side pushes against the ingredient. The angled side pulls the blade in a subtle arc. Together, they let the chef steer the knife through a fillet or a block of tuna as if the steel knew exactly where to go.
It's a small detail. But it changes everything about how the knife moves, how the food responds, and what ends up on the plate.
There's more to the story—about which side gets sharpened, why left-handed knives exist, and what happens when you try to use one the wrong way. Read the full piece on Chaware.
為什麼日本刀只磨單邊?答案藏在武士刀的鍛造傳統裡。
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