Diagonal weave (pattern)
This complex pattern is made up of alternate rows of tall and short rectangles, each crossed with a diagonal stitch. It is a fairly dense pattern and works well in architectural shapes.
Work a diagonal stitch over two vertical and four horizonal threads, top right to bottom left.
Bring your needle up in the original hole, and work three sides of a box around the diagonal stitch in a combination of straight and back stitches.
Work the next row from right to left: this time the diagonal and vertical stitches should be twice the height, so over eight threads.
Structure of stitch
Identifying Diagonal weave (pattern)
A blackwork stitch of blocked zig-zag stitches of alternate long and short zig-zag rows.
Various Authors, The Royal School of Needlework Book of Embroidery (2018) , p.145
Becky Hogg, RSN Essential Stitch Guides: Blackwork (2010) , p.55