Blade Orientation (正刃 vs 逆刃)
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.
| Related: Thinning Rate Guide | Comb Blade Geometry | Tooth Tip Profiles |
Sources
- Naruto Scissors thinning classification system
- Japanese professional thinning technique documentation