This stitch is visually similar to the opened fishbone stitch, but differs technically. This kind of stitch takes a more thread than the opened fishbone stitch.
I will be working on a leaf design, to help illustrate this stitch better. I have divided the leaf into two; technically three. I have named the the stitch lines A, B, C and D. We shall be working between these lines. This stitch is worked from top to bottom.