Kogin is a type of embroidery somewhat similar to Norwegian Hardanger embroidery. You don't create holes in the fabric, but instead create geometric patterns by covering areas of the fabric with a clear, countable weave.
I can imagine that it could be exciting and beautiful to use as a decorative stitch in repairs, on elbow patches, etc., but I haven't had a chance to try it out yet. I have, however, bought it since it's not available in Norway and is strongly linked to sashiko embroidery. Those interested in Japanese crafts will enjoy trying out Kogin!
Kogin originated in northern Japan and was developed to make linen and hemp clothing warmer and softer in winter.
This website provides a good introduction to Kogin in English:
https://davidandcharles.com/2019/09/04/what-is-kogin-embroidery/
Kogin needles are long, with a large eye for the thick thread, and a rounded tip to make counting easier.
You can buy Kogin thread here.