3Dモデル: Nimai-kama-tsugi by thejoinery on Sketchfab
組み立ての要点
Kama Tsugi balances speed of assembly with elegant geometry. Its curved profile diffuses tension, making it perfect for refined interior frameworks. The sickle-shaped lap allows two beams to lock together with compression alone, without visible fasteners. Tea house builders favor it for transoms and lintels where the joint must be both strong and visually restrained.
歴史的背景
Kama Tsugi belongs to the shiguchi family of frame joints used in sukiya (tea house) and residential construction. The curved cut echoes the sickle (kama) shape that gives the joint its name. Unlike heavy temple scarfs, Kama Tsugi prioritizes efficient layout and assembly in interior work where loads are moderate but aesthetics matter. Related sickle-shaped joinery appears in Kama Hozo corner tenons for furniture.
組み立て手順
- Mark the crossing point on both beams; scribe the curved lap profile with an ink marking gauge.
- Saw the curved shoulder on the first member, staying to the waste side of the line.
- Transfer the profile to the mating piece and cut the complementary lap.
- Chisel the waste to create a smooth, tight-fitting curved seat.
- Assemble with a light mallet tap; the compression fit should hold without pegs in many applications.
日本で見られる場所
- Tea houses and tearooms — Kyoto — Uji, Gion, and temple precincts
- Traditional machiya townhouses — Kyoto and Kanazawa — interior framing
バリエーション
Some versions add a wooden pin through the lap for extra security. The curve radius can be adjusted for thicker timbers. Kama Hozo adapts the sickle concept to mortise-and-tenon corner work rather than beam laps.
用途
- Transoms
- Tea house framing
- Decorative lintels
必要な道具
- Ryoba saw
- Chisels
- Ink marking gauge