Also called sashiki 差木, yatoiki 雇木, or machihozo 待ほぞ.
1 A spline tenon. A tenon that is made as a separate piece. Each end of the tenon is inserted into a mortise made on two separate members, for example, to connect a horizontal member to a post. The spline tenon is first inserted into the mortise cut into a post. A draw pin komisen 込栓 (see *sen 栓) is inserted through the post and spline tenon to tighten the joint. Two keys *shachi 車知 are driven into the end of the spline tenon that is imbedded in the horizontal beam because this part is weak and would otherwise be subject to extreme stress.
2 Some spline tenons have a dovetail-shaped end which is inserted into a pillar. In this case the spline tenon is first connected to the pillar and then raised so that the dovetail end can be secured within the matching mortise. Then the beam is inserted into the outer end of the tenon and clinched with keys. This type of spline tenon is generally 35 to 40 mm wide. Spline tenons are employed when the horizontal member is too short to permit cutting a tenon from its end, and used, for example, to connect rainbow beams *kōryō 虹梁 to pillars *hashira 柱.