Wednesday, June 17, 2015

Japanese end joint (Kanawa tsugi)

Inspired by a comment from Sylvain yesterday I found out that I had actually earlier installed a Japanese joint the "wrong" way.
According to the book "The complete Japanese joinery), most of the end joints are supposed to be mounted with the scarfed part vertically. This makes a lot of sense to me, but traditionally in Denmark and it seems also in the USA, those joints are positioned to the scarfed joint is horizontal.

No matter which way you orient it, it is still a pretty cool looking joint in my eyes.

The Kanawa tsugi is translated in the book as a: Half blind tenoned, dadoed and rabbeted scarf joint.

I made four of those in 2011 when I built the interior of the stable. I needed a beam of 14.2 m length out of some 6x6" timber. It doesn't hold any load, but it had to look sturdy to blend in.
The beam holds the upper ends of the posts that form the front corners of the boxes for the horses and also the door openings for the boxes (stalls).

Back when I made the joints, I didn't take any pictures of them, since I hadn't started blogging. But here are a couple of pictures that shows them installed.

Complete joint with cobwebs and dust on 6x6" timber.

The upper beam is made out of four individual
 lengths each joined with Kanawa tsugi end joints.


  1. With just looking at the joint, it is not evident in which orientation it is the strongest.
    A comparison test could only tell if the tradition is right.

    1. Hi Sylvain.

      Maybe I should make a couple of sample joints in a smaller size, and then try to stress them to see in which direction they are strongest.
      But that is a project that I think I'll have to sneak in to convince my wife that I am still working on the porch.


  2. I'm curious, does this joint still need support from underneath, or will it hold up on its own?

    1. Hi Bill

      This joint doesn't need support from below.
      When I made the complete beam, I hoisted it up using 3 chain blocks. It behaved just as it was supposed to: As one structural beam.