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Kama Hozo

鎌ほぞ

A sickle-shaped tenon that locks two timbers at right angles with elegant geometry and strong compression.

Assembly insights

Kama Hozo uses a curved tenon shaped like a sickle (kama) to create a corner connection that resists racking and twist. The geometry channels force through the joint rather than against fasteners, making it ideal for furniture and frames where metal hardware is avoided. Contemporary designers have adapted it for wedged half-dovetail connections that allow disassembly.

Historical context

Kama Hozo (鎌ほぞ) extends the sickle concept from Kama Tsugi beam laps to mortise-and-tenon corner work. The curved tenon profile creates mechanical lock when seated in a matching mortise. Furniture makers and tea house builders use it where corners must resist racking without visible nails. Modern woodworkers have published wedged variants that combine Kama Hozo geometry with knock-down assembly.

Construction steps

  1. Lay out the mortise on the receiving member; scribe the curved profile with a marking knife.
  2. Chisel the mortise to match the sickle curve, keeping walls clean and square to the curve.
  3. Shape the sickle tenon on the mating piece using saws and chisels.
  4. Test-fit; the tenon should slide in with light resistance and lock under corner load.
  5. Optional: add a wedge through the tenon for permanent or knock-down assembly.

Where to see this joint in Japan

  • Tea house and sukiya furniture — Kyoto — interior frames and tables
  • Contemporary Japanese furniture — Tokyo and Osaka design studios

Variations

Wedged Kama Hozo allows disassembly; glued versions are permanent. Curve radius adjusts for timber thickness. Related joints include Kama Tsugi (beam lap), San Mai Hozo (three-piece corner), and standard Hozo Tsugi.

Applications

  • Table legs
  • Cabinet corners
  • Tea house framing
  • Contemporary furniture

Tools required

  • Dozuki saw
  • Nomi chisels
  • Marking knife
  • Square

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