Blade geometry — the cross-section shape — determines how a scissor cuts hair and which techniques it's suited for. Two scissors made from identical steel can feel completely different if their blades are ground differently.
Convex edge (hamaguri-ba)
A convex edge is common in modern professional hair scissors. In Japanese it is called hamaguri-ba (蛤刃, "clamshell blade") because the outside of the blade curves outward in a gentle dome.
Characteristics
- Fine cutting edge — the rounded blade profile can support a smooth cutting action.
- Slide-cutting compatibility — many stylists choose a convex profile for techniques that move along the hair.
- Specialist servicing — preserving the profile requires a sharpener experienced with convex hairdressing scissors.
Many Ichiro cutting models use a convex edge. Suitability for slide cutting, point cutting, blunt cutting, or another technique depends on the individual model and the stylist's preference.
Semi-convex edge
Semi-convex sits between a full convex and a traditional bevel. A small flat facet is left near the edge, keeping most of the convex advantage while improving durability.
This geometry may suit stylists who prioritise durability and controlled wet or blunt cutting. Service intervals still depend on the steel, treatment, use, and maintenance.
Bevel edge
The bevel edge is a traditional scissor geometry, with a visible flat facet ground near the cutting edge. It remains useful in applications such as:
- Barbering scissors for beard and sideburn trimming
- Some thinning scissors (the flat side serves as a stop)
- Some student and entry-level scissors designed for straightforward servicing
Bevel edges are generally straightforward to service and may feel firmer in use. Cutting feel and durability still depend on the complete blade design and steel.
Sword blade
The term "sword blade" commonly describes a blade with a more pronounced spine or outer profile. The exact geometry varies by maker, so it should not be treated as a single technical standard.
Some Ichiro scissors incorporate sword-blade styling. Compare the individual blade profile and intended technique rather than assuming a particular performance from the name alone.
Blade geometry fundamentals
Looking at a scissor blade in cross-section, three regions matter:
- Edge — the working surface that actually cuts. Edge angle determines sharpness.
- Belly — the face between the edge and the spine. Curved on convex, flat on bevel.
- Spine — the thick back that provides rigidity. Thicker spines resist flex better.
Edge angle
Edge angle varies by maker, model, and the way it is measured. A more acute edge can feel sharper, while a less acute edge may prioritise durability. Exact angles and service requirements should be confirmed for the individual model.
Dry and slide cutting compatibility
Stylists who do a lot of dry or slide cutting often prefer a full convex edge for its smooth feel. Bevel and semi-convex profiles can feel different along the hair and may be better suited to other techniques.
For wet cutting and blunt-cut techniques, a semi-convex edge may offer a useful balance of feel and durability. Technique, hair type, maintenance, and personal preference all matter.
How to tell the difference
Hold the blade up to a light and look at the side profile. A convex edge curves smoothly outward. A bevel edge is straight with a clearly visible angle near the edge. Semi-convex falls in between.
The specifications guide explains the main selection factors. Confirm the blade profile of a current Ichiro model with an approved distributor before ordering.