For a 3(4, 5) st buttonhole. Work to where you want the buttonhole to begin, bring the yarn to the front, slip the next stitch purlwise, and then return the yarn to the back.
1. *Slip the next stitch. Then on the right needle, pass the second stitch over the end stitch. Repeat from * 2 (3, 4) times. Slip the last bound-off stitch to the left needle and turn the work.
2. Move the yarn to the back and use the cable cast on to cast on 4 (5, 6) stitches as follows: *Insert the right needle between the first and second stitches on the left needle, draw up a loop, and place it on the left needle. Repeat from * 3 (4, 5) times. Turn the work.
3. With the yarn in back, slip the first stitch from the left needle and pass the extra cast on stitch over it to close the buttonhole. Work to the end of the row.