Several systems exist for designating joints. The terminology is not standardized. As pointed out in the authors’ comments, this book aims at describing a wide variety of splices and joints, describing them in detail. However, no pretense is made of giving an accurate designation for all of the joints, nor do we try to explain the origin of the appellations selected.
The following terminology’ should provide some help in understanding the technical terms employed.
Beam (hari): horizontal structural element which receives loading from a roof or a floor and transmits it to the columns.
Girder (keta): horizontal structural element within the framework of the external wall perpendicular to the tie-beam.
Girt (dosashi): horizontal structural element within the framework of the external wall intersecting the second floor beam perpendicularly.
Eave socket (udegi): Bracket anchoring the cave rafters onto a beam or a girder. When the cave rafters arc not braced perpendicularly, the cave socket must be designed to carry a moment (cantilever cave rafter).
Hanging post (tsurizuka): Hanging posts are used to suspend the lintel from a beam or girder when column height exceeds 2.7m.
Tie (nuki): Bracing element within the internal framework of a wall running between columns.
Male-female: The positive and negative part of a splice or joint.
Upper wood-lower wood: In connection with joints, the upper and lower wood refer to two identical ends of a splice or a joint. When assembling the joint, the part which is joined onto the end already in place is called upper wood. The other end is the lower wood.
Example: Rabbeted oblique scarf splices and oblique scarf stub tenon
Stub tenon (daimochi): When the lower wood is meant to be exposed to the vertical load from the upper wood over the entire section of the joint, the assembly is called stub tenon.
Example: Blind stub tenon and tic stub tenon
Stepped joint (koshikake): When the male end of a joint is stepped to transmit a vertical load onto the female, or vice versa, the joint is said to be stepped.
Example: Stepped dovetail splice and stepped gooseneck splice
Dovetail (ari): The part of a joint shaped like the tail of a dove, narrow at the girth then flaring out.
Example: Dovetailed splice, housed dovetail splice and halved dovetail Tenon (hozo): A projection at the end of the male part of a joint.
Example: True tenon and mortise, rabbeted tenon, dovetailed tenon, blind wedged tenon
Gooseneck (kama): Refers to the ribbed end of a long tenon.
Example: Stepped gooseneck with tenon and mortise and square stepped gooseneck with tenon and mortise
Tongue and groove/tongue (mcchiirc-mechihozo): Refers to the joining of two elements. A long and narrow tenon (tongue) covers the length of the end surface of the male; an equivalent groove is carved on the end surface of the female.
Blind joint (hako): Refers to an encased tenon shaped like the letter “L” or the Japanese капа “э” (ко).
Example: Blind tenon and mortise, blind stub tenon, blind pin and blind splice Crossbilled or halved joint (isuka): Refers to a joint where the male and female arc shaped like the beak of a crossbill finch.
Example: Halved rabbeted oblique scarf splice, triple-faced and quadruple-faced rabbeted oblique scarf splice, Miyajima splice Miter joint (tome): When an inclined seam is located at the intersection of two members, the seam is called miter.
Drawpin (komisen): Two types of drawpin are used to tighten a joint. Some pins work in shear (type A) the other type withstand crushing pressure (type B)
A) rabbeted oblique scarf splice, double-faced plug, triple-faced plug
B) Mortise rabbeted oblique scarf splice, housed rabbeted oblique scarf splice, blind
Key (shachi): Locking element inserted into a key hole through the sections under shear.
Example: triple-faced halved joint, Miyajima, blind stub tenon, corridor girder, etc. Wedge (kusabi): Tapered triangular element pounded between two surfaces, driving them apart from each other.
Example: wedged through halved dovetail, blind wedging joint, wedging joint, etc. Dowel (dabo): Encased element inserted into a cavity passing through two joining surfaces. Example: stub tenon on tics