Kiritsuke Tsugi 切り付け継ぎ

Assembly insights

Kiritsuke Tsugi is the most basic form of Japanese scarf joint. Two members receive opposing tapered cuts at angles typically between 1:8 and 1:10, creating long-grain-to-long-grain contact for strong gluing surfaces. Unlike complex temple-grade tsugite, it relies on adhesive and clamping rather than mechanical interlock. It serves as an excellent introduction to angled layout and saw control before advancing to Kanawa Tsugi and Okkake Daisen Tsugi.

Historical context

Kiritsuke Tsugi represents the foundational lengthening joint in Japanese carpentry. Its simple geometry predates the more elaborate temple-grade scarfs and remains in use today for non-structural applications, repair work, and as a teaching joint. Students master angled cuts and grain orientation here before tackling Kanawa Tsugi and Okkake Daisen Tsugi.

Construction steps

1. Mark the scarf angle (typically 1:8 to 1:10) on both pieces using a marking gauge and square.
2. Saw the angled faces on each member, ensuring they are complementary.
3. Plane the mating surfaces flat and square for maximum gluing contact.
4. Apply adhesive and clamp firmly along the length; allow to cure before handling.

Where to see this joint in Japan

• Traditional house construction — Throughout Japan — non-structural beam extensions

Variations

The scarf angle can be adjusted: steeper angles (1:8) provide more gluing surface but require longer overlap. Some variants add a single dowel or pin for extra security. For structural use, Japanese craftsmen typically advance to mechanically locked scarfs like Kone Tsugi or Kanawa Tsugi.