Shinobu Kobayashi, a Japanese woodworker, is currently studying that craft in Sweden. In this .gif, he demonstrates the flexibility and utility of the kawai tsugite joint, which was invented by a professor at Tokyo University.
Master woodworker Matthias Wandel, whose work we've featured extensively, shows in this video how to make this kind of joint. It's a very complex job that requires a bandsaw, a router, and an enormous amount of patience.
Wandel is impressed with the geometry and flexibility of the kawai tsugite joint, but concludes that's it's needlessly complex and is too fragile to stand up to pressure.