Lit. hell tenon. So named because once it is inserted, it is impossible to withdraw. A blind tenon joint with wedges *kusabi 楔 inserted tightly into slots made on its end. It is important first to place the wedges loosely into the slots to inhibit premature horizontal spreading of the tenon. The base of the tenon is large enough to fit the dovetail-like, tapered shape of the mortise *hozoana ほぞ穴. When the tenon with wedges is pounded into the mortise, the wedges cause the tenon to expand to fit the sides of the mortise. Only the wedges extend the depth of the mortise. The tenon itself does not. Wedges may also be placed on each side of the tenon. The jigokuhozo joint is used where it is necessary that it be hidden, for example on bracket complexes under the eaves of a building, in furniture and cabinet making, and especially in joinery used in the shoin style *shoin-zukuri 書院造.

