Blade Orientation (正刃 vs 逆刃)

Reference sectionBlade Orientation in Thinning Scissors (正刃 vs 逆刃)

Blade orientation in thinning scissors is a construction field: it records which blade carries the teeth and which carries the continuous cutting edge. It is separate from handedness, handle symmetry, tooth count and cut rate. It does not, on its own, settle how much hair a shear removes or how it blends.

Quick look

• 正刃 (seiba): Smooth blade moves; the toothed comb blade stays static. Standard thinning orientation
• 逆刃 (gyakuba): Comb blade moves; straight blade stays still
• 両櫛 (ryōgushi): Both blades are toothed; makers present these as their lowest-removal configuration
• Japanese classification: 二梳き (ni-suki), 三梳き (san-suki), 四梳き (yon-suki) per Naruto system

Why it matters

In thinning scissors, orientation tells you which blade moves and which stays still. The tooth design and the maker’s stated use tell you more about the finish.

正刃 (seiba): standard orientation. The smooth cutting blade is the moving blade, while the toothed comb blade is the static blade. When the scissors close, the smooth blade travels across the stationary comb teeth. This is a construction description, not a guarantee of rate, feed or finish: it is the layout Hikari’s selection guide and Naruto’s S code use.

逆刃 (gyakuba): reverse orientation. The comb blade is the moving blade. Some makers and sellers position specific reverse models for fades or blending (ボカシ, bokashi); that advice belongs to those models, not to every reverse thinner.

両櫛 (ryōgushi): double-comb. Both blades are toothed. Because teeth on both sides interact, hair is cut only where it falls into the gaps of both blades at once, and the makers present these as their lowest-removal, subtlest-texture configurations. What that costs in rate is not fixed by the construction: tooth count, tooth pitch, the ground finish and the maker’s stated use all move it. Do not infer from the double-comb layout alone that a shear removes less than a single-comb one.

Naruto Scissors uses 二梳き (ni-suki), 三梳き (san-suki) and 四梳き (yon-suki) for families of multi-stage tooth and comb shapes rather than for a count of passes, which the maker presents as progressively finer and more blended stages.

DetailMaker codes are house codes

Orientation is usually printed as a maker’s own letter or icon rather than a shared symbol, and the codes do not transfer between brands. Hikari defines standard and reverse by which blade moves in its thinning-shear selection guide. Naruto uses S for its static-comb layout and B for its moving-comb layout, with the trailing number giving the tooth count. KASHO uses A/B position icons in its catalog, and they have to be read as KASHO defines them rather than converted into Naruto’s letters or another brand’s standard/reverse labels. Read each maker’s diagram and its own definition, and record orientation separately from handedness, handle symmetry, and whether the model can be flipped or ordered in the other orientation.

Source trailSources and limits

Orientation is described here from maker-published definitions and diagrams: Hikari’s thinning-shear selection guide (standard means a moving solid blade, reverse means a moving comb blade), Naruto’s S and B layout codes, KASHO’s own A/B tooth-position icons, and Japanese professional thinning-technique documentation. Each definition belongs to the maker that publishes it and does not transfer to another brand’s letters.

No removal rate is given for either orientation, because orientation does not determine one. Tooth count, tooth profile, width and spacing, groove arrangement, comb arrangement, blade set, section, angle and number of closes all move the observed result. Treat a seller’s direction-of-use advice, such as reverse models positioned for fade blending, as instruction for that named model rather than a rule about reverse shears in general.

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