I have three jeans to mend. A few days ago I mended one of my daughter's using scraps of denim and sashiko stitching.
Below: My grandma sewed these mu mus below. I used to wear these myself when I was in high school. I photographed them recently at my parents' house. The stitch work strengthens the fabric and is very decorative. It is not sashiko, but it is traditional Japanese stitch work. I do not know what it is called. I recognize the star like pattern from other Japanese soft goods like pillows. The linking stitch work I have seen on other worker garments. I just found this posting on Japanese darning on Hand Embroidery Network and think such darning is the origins of this decorative yoke. I also found this article showing Japanese stitching and darning.