This cast on provides a set of stitches that can be picked up later and used to knit in the opposite direction.
This method starts with a contrasting color yarn that will be removed later to expose the stitches.
Using a contrast color waste yarn make a slip knot on your crochet hook to start. With the knitting needle held upright on the left and the crochet hook on the right, bring the yarn from the crochet hook on the right, behind the needle and towards the left and forward towards yourself. Moving the crochet hook in front of the needle, catch the yarn which is now to the left of the needle and pull this yarn through the loop on the crochet hook. This makes one stitch. Repeat this until you have the desired number of stitches on your needle. Pull a large loop through the loop on the crochet hook to prevent the crochet work from unraveling (and/or create a chain).
When you are ready to use the stitches being held by the crochet work, pull the loops of the waste yarn out and the working stitches will be freed and ready to be put on the needle for working. Be careful to place each stitch on your knitting needle as the waste yarn is pulled out of it. You will have one less stitch than what you cast on with.