kai no kuchitsugi 貝の口継

Keywords
Architecture
Joints

Lit. shell mouth joint. A straight end-to-end joint *tsugite 継手 used for very tall pillars that must be assembled in two or three sections. The timber sections are cut into four sections in an x shape. The inner parts of the cuts have a raised collar *eriwa 襟輪 while the two remaining parts of the x are spliced down to a length slightly longer than the diameter of the timber. At the base of these long cuts, there are small grooves into which the collars of the abutting piece fit. Thus the two parts are tightly secured. This joint is used most frequently to join the parts of the central pillar *shinbashira 心柱 of a pagoda. The joint resists twisting but is said to be somewhat weak in regard to tensional deformation.