Blade Spine (峰)
Description
The blade spine (mine) is the thick back edge of a scissor blade that provides structural rigidity. Learn how spine thickness affects weight, balance, and durability.
Blade Spine (峰, みね / Mine)
Quick look
- What it is: The non-cutting upper edge of the blade, opposite the sharpened edge
- Purpose: Provides structural rigidity, determines blade balance, and defines the cross-section profile
- Key relationship: Cross-section types are named after their spine profile (hamaguri-ba, dan-ba, ken-ba)
- Japanese term: 峰 (みね, mine)
Why it matters
The spine is the structural backbone of the blade. Its thickness and profile determine how rigid or flexible the blade is, how much it weighs, and how it distributes force during cutting. Every blade cross-section, from hamaguri-ba (clam-shaped) to dan-ba (stepped) to ken-ba (sword), is defined by the shape of the spine relative to the cutting edge.
Thicker spine = more rigid, heavier. A thick spine resists torsion and flex, keeping the blade perfectly straight under load. This matters for power cutting through dense hair, scissor-over-comb work, and any technique where deflection would compromise accuracy. The trade-off is weight, and a heavier blade accumulates more fatigue across a full day of cutting.
Thinner spine = more flexible, lighter. A thin spine allows the blade to flex slightly, which some stylists prefer for slide cutting and softer techniques. The lighter weight reduces fatigue but also reduces the blade’s ability to power through resistant sections without deflection.
The spine profile also affects balance. A blade with more mass concentrated in the spine will have a different center of gravity than one with an even distribution. This interacts with handle design and pivot position to determine where the scissors balance in the hand.
When evaluating scissors, pay attention to the spine. Run your finger along it. A smooth, consistently profiled spine indicates careful grinding. Irregularities suggest shortcuts in manufacturing that may affect performance.
| Related: Hollow Grind | Blade Curvature | Blade Cross-Section |
Sources
- Japanese blade cross-section classification systems
- Professional scissor manufacturing technical references