Miyajima-tsugi

Miyajima-tsugi, known in English as overlapping mortise and tenon joints, is a specialty joinery method developed on Miyajima Island off Hiroshima. With this technique, oversized mortises are chiselled partway into the width of horizontal beams. Corresponding tenons projecting from upright posts are sized to slot fully inside and extend from both exposed faces of the beam. When joined, the longitudinal grain of each tenon crosses the end grain of the beam, wedging tightly from both directions. Called Miyajima-tsugi after its place of origin, this counter-grained connection requires exacting skill yet creates extremely strong, flexible intersections. By reinforcing perpendicular wood fibers, the traditional technique allowed Miyajima Island's historic Torii gates and shrines to endure considerable structural loads through centuries of storms and earthquakes without hardware. Through cross-lamination of fibers, Miyajima-tsugi exemplifies the ingenuity of Japanese woodcraft.