
The protruding corners represent kiriau, the central line is ikarari, and the thick red line is oho.
If you're interested, look up terms like Chijiri and Kaparamipu.
As for the design, there seem to be rules, or maybe not. I designed it while learning from Mr. Tsuda, but naturally, much of it is intuitive. For someone like me who tried it on a whim, it was still far beyond my understanding.
Actually sewing it
Mr. Tsuda also taught me the embroidery techniques. I had learned a bit from Tsuda-san's published books, but learning directly from her was much clearer. She also taught me things not written in the books, like "You can also do it this way." I put that into practice, but paying attention to things like how even the stitches were made turned it into such meticulous work that hours flew by instantly. My shoulders got so stiff, I've never felt this kind of stiffness before (laugh). The concentration of the Ainu people who did this on the scale of clothing is incredible.

Learning sewing techniques.
Ainu patterns evolved over generations, passed from mother to child, developing curves and other changes. It's truly a shame that today we can only recreate them. I pray this fine traditional craft isn't lost.
Thank you, Tsuda Meiko, for teaching me so much about Ainu history, patterns, and various other things.