Convex edge fundamentals
Convex (hamaguri) edges are ground in a smooth clam-shell curve that flows from spine to tip without a hard angle. That geometry—documented in the blade geometry reference—delivers the soft glide you feel during slide cutting and point detailing.
| Attribute | Benefit | What to watch |
|---|---|---|
| Continuous curve | Hair glides without snagging, ideal for slide and slither work | Needs premium steel (60+ HRC) to hold shape |
| Hollow-ground interior (urasuki) | Reduces friction so blades only meet at the cutting point | Requires precision tension checks |
| Polished edge | Produces mirror finish that resists corrosion in humid salons | Avoid abrasive cloths; stick to chamois |
When convex edges outperform other grinds
Slide cutting
The curved face lets hair travel along the blade without stopping, so you can remove weight with minimal resistance. Pair convex shears with VG-10 or cobalt steels for long booking blocks—see the VG-10 vs 440C guide for upgrade timing.
Point cutting & detailing
A razor-sharp tip produced by convex geometry allows you to notch cleanly without collapsing the strand. Keep tension light and elbows dropped to avoid introducing micro-nicks.
Texturising on dry hair
Convex blades maintain smoothness even when dry sections fight back. Combine them with thinning shears that feature U-shaped teeth (see Fuji MoreZ insights) for snag-free blends.
From Experience: If your slide work starts dragging, you are either overdue for a convex specialist sharpening or your tension is pinched too tight.
Maintenance requirements (non-negotiable)
- Daily: Wipe, dry, and oil following the daily care ritual. Avoid microfiber cloths that can scratch the polish.
- Tension: Check using the drop test outlined in the maintenance pillar. Convex geometry fails fast if you clamp the pivot.
- Sharpening: Book flat-hone technicians only. The sharpening protocol lists the interview questions. Expect 8-12 month cadence on VG-10, up to 18 months on premium cobalt.
- Transport: Store in hard cases and use blade guards; chips from travel negate the convex advantage immediately.
Choosing the right convex shear
| Stage | Recommended approach |
|---|---|
| Apprentices | Stick with 440C or VG-10 convex hybrids from Mina/Ichiro while building tension habits. |
| Emerging pros | Step into VG-10 options like Juntetsu Sword or Ichiro K10 for longer edge life and balanced ergonomics. |
| High-volume stylists | Invest in premium convex lines (Mizutani ACRO, Hikari Cosmos) with RSI-friendly handles from the brand directory. |
Cross-check tool choices with the tool profiles hub so your thinning shear pairs share balance and tension.
Troubleshooting drag or push
- Symptom: Hair slides but blade feels dull mid-stroke.
Fix: Clean and oil, then re-run the drop test. If tension is correct, schedule a specialist sharpen. - Symptom: Tips fold hair on point work.
Fix: Inspect for micro-nicks under bright light; chips require professional honing. - Symptom: Blade pulls during scissor-over-comb.
Fix: Convex edges are not designed for hard blunt work—swap to your beveled workhorse.
Document every issue in your maintenance log. Patterns help you decide when to rotate blades or upgrade steel.
Next actions
- Audit your current convex shear using the authenticity checklist.
- Schedule your next sharpening using the service protocol.
- Practise slide and point drills from the technique hub to keep muscle memory aligned with the edge.
Need help diagnosing a stubborn issue? Send details via the contact page with photos of the edge and your maintenance log.