Threaded Herringbone Stitch
To work threaded herringbone stitch first work a row of herringbone stitches. Starting on the top row working from right to left, bring your needle up at 1 and then thread it under the right diagonal above the crossed end and then over the left diagonal as seen in the picture below. Repeat along the row. Then to thread the second row bring the needle up at 2 and working in the same way, but this time passing the thread below the crossed end.