This stitch is called Zig-zag Chain Stitch but is also known as Vandyke chain stitch. Needless to say Zig-zag chain is a member of the Chain Stitch family.
Zig-zag chain stitch is effective when worked alone or if you stack it sewn row upon row you can build up patterns for borders. As you can see from the sample taken from one of my crazy quilt blocks it also looks great used to secure ric rac!
Work the zig zags from left to right between two imaginary parallel lines or mark your work with a quilters pen that is removed when you add moisture.
Bring the needle up through the fabric on the bottom line and insert the needle back into where it came out and take a bite of the fabric to have the needle emerge on the top line, a short diagonal space along. With the thread wrapped under the needle point pull the needle through the fabric.
Point your needle back into where it came up from the fabric and take a bite of the fabric to have the needle emerge on the bottom line, a short diagonal space along. With the thread wrapped under the needle point pull the needle through the fabric.
Continue along the line working each loop at right angles to the previous loop to create the zigzag line.
If your loops flip up as you enter the fabric with each loop pierce the end of the previous loop. This will ensure that each section of the chain lies flat.
This sample is zig-zag cable chain. It is simply cable chain worked in a similar manner to regular zig-zag chain