Hong Kong Seam
It is a type of bound seam. The edges of the seam are encased in a fabric binding, usually bias tape. To make a Hong Kong seam, cut a bias strip the width of a seam allowance plus ¼”. Place the bias strip on top of the seam allowance, right sides together. Stitch 1/8” from raw edges. Fold the bias strip over the raw edge and around to the underside. From the top side, stitch in the ditch or groove formed by the previous stitching, catching the bias strip underneath. Press the seam open.