I could go the easy route and just bolt, screw or nail some together, but this is part of what I really like to be doing, so I didn't want to cheat myself from trying out a nice carpentry joint.
The Okkake daisen tsugi is also sometimes called Wari tsugi. In English it would be called a "Dadoed and rabbetted scarf joint".
My main source of inspiration for these joints is the book: The complete Japanese joinery, published by Hartley and Marks.
That book is an absolute treasure trove of information on the subject. There is even a description of the religious ceremony to be held prior to building a new home.
I can highly recommend the book to anyone interested in the subject of Japanese timber framing joinery.
Using hand tools only, it takes me roughly one hour and fifteen minutes to complete both joints on a set of 3x6" planks to be joined.
I need to complete a total of six long planks, so I might even get a bit faster when it comes to the last joint.
Today it is raining, and all the concrete pillars have been poured, so it is a welcome change to do some work in my workshop.
The female part of an Okkake daisen tsugi.
The set up, sawhorse and shop stool.
Halving the dado.
The completed joint.
This is about the maximum length that is workable inside the shop. (6.5 m)
The tools used to make the joint.