The sashimi knife. Being A blade ground to an edge on only one side, with a flat or hollow back; it cuts straighter and finer but takes more skill to sharpen than a double bevel. means the flat ura (the back face) holds the fish flat against the blade, producing a cut surface that is perfectly flat rather than slightly curved, as a double-bevel blade would leave it. This is the technical reason sashimi from a skilled A sushi restaurant, or the chef who runs it. has that distinctive clean, flat-cut appearance.
Technique: the cut requires a single, uninterrupted draw cut. The blade is longer than the fish slice, so one stroke from heel to tip completes the cut. Multiple strokes (sawing) compress the fish cells and degrade the texture.
Primary tasks: slicing raw fish for sashimi and sushi with a single-pull, no-sawing draw cut that severs proteins cleanly without crushing cells, preserving the translucent appearance of a perfect slice.
Ideal steel: the finest possible edge. Shirogami #1 is the traditional professional choice; Aogami Super gives better retention; Ginsan or SG2 for stainless.
Limitations: it cannot be used left-handed without a mirror-ground left-hand version (a special order); the standard is right-handed. It is a lifetime investment, getting better as it is properly sharpened and learned.