Closed diagonal darning (pattern)
Work a series of straight horizontal parallel stitches over five fabric threads. Each stitch should be offset horizontally by one fabric thread from the stitch above.
Work back up the shape repeating the same stitch over five threads, ensuring each stitch shares a hole with the previous stitch on that line.
Structure of stitch
Various Authors, The Royal School of Needlework Book of Embroidery (2018) , p.153