Kogin is a type of embroidery that is somewhat reminiscent of Norwegian Hardanger embroidery. Geometric patterns are created by covering areas of fabric with a distinct, countable weave.
I can imagine it would be exciting and lovely to use as a decorative stitch in repairs, on elbow patches, etc., but I haven't had a chance to try it out yet. However, I have purchased it since it's not available in Norway and is strongly linked to sashiko embroidery. Those interested in Japanese craftsmanship will enjoy trying out Kogin!
Kogin was developed because hemp fabric was the only material available to poor farmers in Japan between the 17th and 19th centuries. It was a very cold and rough fabric. By using counted stitches with thick thread, a softer surface and more insulation were created.
This website provides a good introduction to Kogin in English:
https://davidandcharles.com/2019/09/04/what-is-kogin-embroidery/
Kogin thread is thicker than sashiko thread and quite soft. It is therefore best used on slightly loosely woven or knitted garments. (It can be very nice as embroidery on knitwear as an alternative to shinier embroidery thread or completely matte wool thread!)
Use a needle with a large eye and a rounded tip, or buy dedicated Kogin needles here.