When teaching my finishing classes, I am often asked about working neat buttonholes. I’ve tried many different techniques over the years and never loved any of the results – they seemed to sag and stretch – so I often avoided buttonholes completely.
But then I tried my technique for a neat underarm bind-off (when knitting a sweater bottom-up) and found it resulted in a neat, almost invisible hole. This method also hides the holes in the valleys created by purl stitches on the right side. I’ve given directions for both a one-stitch buttonhole in k1, p1 rib and a two-stitch buttonhole in K2, P2 rib.