Blade Orientation (正刃 vs 逆刃)
Tooth typesKeep count, construction, published rate, and trial together
Tooth count is one descriptor; geometry and model-specific maker data can produce different published ratios at the same count. Apply to Blade Orientation (正刃 vs 逆刃)
- 01 Count Use the maker's counted teeth, zones, and per-blade convention.
- 02 Geometry Record profile, width, gaps, grooves, overlap, and escape path.
- 03 Arrangement Name one- or double-comb construction, orientation, and handed model.
- 04 Result evidence Keep any published ratio model-specific and use a controlled trial.
Do not inferCount, a tooth-name, or a retail label cannot supply a universal removal percentage, hair-type match, placement, or result.
Description
Seiba vs gyakuba refers to normal vs reversed blade orientation in thinning scissors. Learn how blade direction affects thinning rate, line visibility, and technique.
Blade Orientation in Thinning Scissors (正刃 vs 逆刃)
Quick look
- 正刃 (seiba): Smooth blade moves; comb blade stays on top (static). Standard thinning orientation
- 逆刃 (gyakuba): Comb blade moves; produces an upward-pull action. Used for fade blending (ボカシ/bokashi)
- 両櫛 (ryōkushi): Both blades are toothed, producing a very low cut rate
- 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, which blade moves and which stays static fundamentally changes the cutting behavior, the direction of pull on the hair, and the type of finish produced.
正刃 (seiba) — standard orientation. The smooth cutting blade is the moving blade, while the toothed comb blade sits on top in a static position. When the scissors close, the smooth blade moves upward against the stationary comb teeth. This is the most common configuration and produces standard thinning results: predictable, even removal with the hair being cut falling away cleanly. Most thinning scissors sold worldwide use this orientation.
逆刃 (gyakuba) — reverse orientation. The comb blade is the moving blade. When the scissors close, the toothed blade moves downward, creating a subtle upward-pull on the hair. This pulling action is what makes gyakuba thinners the preferred tool for fade blending work, known in Japanese as ボカシ (bokashi). The upward pull lifts and separates the hair during cutting, producing the seamless gradient transitions that define quality fade work.
両櫛 (ryōkushi) — double-comb. Both blades are toothed. Because teeth on both sides interact, only hair that falls into the gaps of both blades simultaneously gets cut. This results in a very low cut rate and extremely subtle texture removal. A specialty configuration for finishing work where minimal, controlled removal is needed.
Naruto Scissors classifies thinning scissors by the number of comb-blade passes relative to the smooth blade: 二梳き (ni-suki, two-thin), 三梳き (san-suki, three-thin), and 四梳き (yon-suki, four-thin), describing progressively finer removal increments.
Sources
- Naruto Scissors thinning classification system
- Japanese professional thinning technique documentation
See Also
Frequently Asked Questions
3 answers you can open one at a timeWhat's the difference between seiba and gyakuba thinners?
It comes down to which blade moves during the cut. In 正刃 (seiba, standard orientation) the smooth cutting blade moves upward while the toothed comb blade stays static on top — the most common configuration worldwide, producing predictable even removal with clean release. In 逆刃 (gyakuba, reverse orientation) the toothed blade moves downward instead, creating a subtle upward pull on the hair during closure. The moving blade changes the direction of force on the hair and, with it, the finish the scissor produces.
When would you reach for a gyakuba (reverse-orientation) thinner?
Gyakuba is the preferred tool for fade blending work — what Japanese stylists call ボカシ (bokashi). The upward pull from the moving comb blade lifts and separates hair during the cut, producing the seamless gradient transitions that define quality fade work. Seiba thinners cut the hair cleanly but do not lift it; for fade blending that lift is what makes the difference between a visible boundary and a gradient that disappears into the style.
What hair types and techniques suit Blade Orientation (正刃 vs 逆刃)?
両櫛 (ryōkushi) thinners have teeth on both blades rather than just one. Because teeth on both sides must align for a cut to happen, only hair that falls into the gaps of both blades simultaneously gets removed — which produces a very low cut rate and extremely subtle texture change. Ryōkushi is a specialty configuration for finishing work where minimal, controlled removal is needed. Naruto Scissors classifies variants by tooth pass count: 二梳き (ni-suki, two-thin), 三梳き (san-suki), and 四梳き (yon-suki).
Comments & questions
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