Continuous thread stitching (a.k.a. continuous dart) is a nifty sewing technique in which the sewing machine sews with the bobbin thread only to avoid doing a back stitch at one end. It's helpful when sewing darts in sheer fabric.
Continuous Thread Sewing
Tag: back stitch
Back stitch
The back stitch is a great hand stitch to use for adding detail to your designs.