Kogin is a type of embroidery that is somewhat similar to Norwegian Hardanger embroidery. Geometric patterns are created by covering areas of fabric with a distinct, countable weave.
I can imagine that it could be interesting and beautiful to use as a decorative stitch in repairs, on elbow patches, and so on. These kits are designed to make coasters, but can also be used for patches. They are, in any case, a great introduction to the technique!
Kogin was developed because hemp fabric was the only fabric available to poor farmers in Japan between the 17th and 19th centuries. It was a very cold and rough fabric. By using counted thread embroidery with thick thread, a softer surface and more insulation were created.
The kit contains 2 skeins of kogin thread, 1 kogin needle, and fabric for the counted embroidery and for the back of the coaster. Copies of the instructions in English are also included (along with Japanese instructions inside each kit). The kits come in plastic bags as shown in the pictures.