Kanawa Tsugi
A scarf joint reinforced with a metal collar to resist bending and seismic stress. Revered in temple restoration.
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Joint profile
Okkake Daisen Tsugi 送掛大栓継ぎ
An oblique housed and rabbeted scarf joint with through-tenon keys, used to join timbers end-to-end for foundation and structural work.
Assembly insights
Okkake Daisen Tsugi combines a dadoed rabbet with a stepped scarf, creating a joint that cannot be slipped together sideways. The piece with the inverted T-tenon must be inserted lengthwise, then locked with draw pins (komisen) or keys (shachi). The joint became feasible during the Edo period as carpenter's tools improved, and it remains a hallmark of structural joinery for traditional buildings.
Applications
- Foundation footings
- Wall plates
- Eave purlins
- Sliding door tracks