The simplest method of casting on, the Backward Loop cast-on is also called the single cast-on or simple cast-on. It involves adding a series of half-hitches to the needle.
Benefits and Drawbacks
It creates a very stretchy, flexible edge. It is a common approach for adding several stitches to the edge in the middle of a knitted fabric, but it is difficult to knit from and make even.
After placing a slip knot on the needle, hold the needle in one hand and the working end of the yarn in the other. Hold the thumb of the yarn-hand in the air, like a “thumbs-up.” Rotate the thumb down and toward the body, between the working end and the body, then up and behind the working end, and back to a “thumbs-up,” creating a loop around the thumb. Slide the needle point from the palm along the thumb toward the thumbnail, underneath the yarn loop. Slip the thumb out and tighten the loop with the working end. One stitch created. When knitting the first row, the original slip knot can be knitted as an additional stitch or dropped and pulled out.
A variation of the Backward Loop cast-on is the twisted simple cast on, where you twist the new loop around the thumb, with the yarn going around the back of the thumb to the front as in the simple cast-on, but picking up the new loop from the back side of the loop. This is tighter and neater, but has less elasticity.