Closed feather stitch
This is a variation of feather stitch where each stitch is closed to form a triangle.
This stitch is very similar to double chain stitch: for double chain, the loop of the chain is taken down inside the loop of the previous chain; for closed feather, the needle is taken down just outside the previous loop.
N.B. Historic references to closed or close feather stitch may be referring to long and short stitch (feather stitch is an alternative name), rather than this stitch.
Imagine (or draw) two parallel lines and bring your needle up on your left line. Take your needle down on your right line at slightly higher point than where you emerged on your left line.
Leaving a loop, bring the needle up on your right line, but a little lower than where you first brought the needle up. Pull the thread to create a triangular stitch.
Take the needle down on the left line in the same hole that you first brought the needle up.
Leaving a loop, bring the needle up on your left line, but a little lower than where you brought the needle up for the second stitch.
Pull the thread to create a second triangle. Then take the needle down on your right line very close to the spot where the second stitch started, but make sure it is outside the loop.
Leaving a loop, bring the needle up on your right line, but a little lower than where you started the third stitch. Pull the thread to create another triangle.
Continue working in the same way. When finishing the stitch, take the needle down over the last loop to form a small anchoring stitch.
This completes your line of closed feather stitch.
Mrs Archibald Christie, Samplers and Stitches (1921) , p.31–2
Mary Thomas’s Dictionary of Embroidery Stitches (1934) , p.93
Jennifer Campbell, Ann-Marie Bakewell, Guide to Embroidery Stitches (2004)
Sarah Whittle, The Needlecraft Stitch Directory (2012)