Plaited braid stitch

This stitch consists of interlocking loops of thread which form a solid raised line of zigzag threads. The majority of the thread remains on the surface of the stitch.
N.B. Braid stitches have been popular through history, particularly in the Elizabethan era where many versions were used, but they were not well-documented. This means that historical references to ‘braid stitch’ may refer to any of the many versions (including Heavy chain stitch), rather than specifically this stitch.
However, research has shown that this plaited braid stitch has its origins in the Bronze Age – a woman buried in South Jutland, Denmark in approximately 1300BC wears a blouse embellished with this stitch. More recently, this stitch was used extensively in Elizabethan embroidery, most commonly using metal threads. The Victoria and Albert Museum, London holds many examples, including a coif and forehead cloth which show a quintessentially Elizabethan design of flora with curvilinear lines executed in plaited braid stitch using metal thread.
Method
Bring your needle up at the end of the bottom guideline and make a loop with your thread. Take your needle down inside the loop on the top guideline (a short distance from the end), and back up on the bottom guideline, over your working thread. Your needle should emerge level with where it went down.
Use your needle to manipulate both sides of the braid so it resembles a pretzel.
Motion 1: Slide your needle under where the threads form a cross, from top to bottom, without piercing the fabric. Your needle should go over the top outer loop of the pretzel, under the cross and over both your working thread and the bottom outer loop of the pretzel. Pull your thread through.
Use your needle to manipulate both loops of the braid so it resembles a pretzel.
Motion 2: Take your needle into the fabric on the top guideline, inside two loops of thread. Bring it back up on the bottom guideline over your working thread and the outer loop.
Ensure that the needle emerges outside of the diagonal thread of the pretzel. You may find it helpful to use a tapestry needle or mellor to open up the second loop in order to bring your needle up.
Continue working the braid by repeating Motion 1 and Motion 2, alternately. Adjusting the loops of the pretzel after each motion makes it easier.
When you have reached the desired length, bring your needle out next to one of the loops and anchor it with a small stitch.
Repeat the small anchoring stitch on the other loop.
A completed length of plaited braid stitch.

Common uses
Embroidery Techniques
Identifying Plaited braid stitch
This stitch can be identified by the pattern of braiding: two diagonal threads form a central V shape, encased by curved edges.
The majority of the thread is on the surface of this stitch: the reverse only shows parallel horizontal stitches (like the rungs of a ladder) which span the width of the braid.
References
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Sarah Whittle, The Needlecraft Stitch Directory (2012)
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Karen Finch. (1991) 'Needlework fabrics', Journal of Museum Ethnography pp.15-28. Available at: https://www.jstor.org/stable/40795033
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'Elizabethan coif and forehead cover', Victoria and Albert Museum (2021). Available at: https://collections.vam.ac.uk/item/O251205/coif-and-forehead-unknown/ (Accessed: 13 October 2021)