This cast on techniques allows you work your project on2 opposite directions (one after the other). The provisional stitches are first worked in one direction, then, you can pick them up again to work them on the opposite direction.
To work this cast on, you will need a needle (circular or straight depending on your project), a crochet hook the same size as your needle, the yarn for your project and a scrap piece of yarn.
Casting the stitches on
With your scrap piece of yarn, form a loop with a slipknot.
Place this loop on the wrochet hook and tighten it.
With the nedle in the left hand and the crochet hook in the right hand, place the strand under the needle.
With the crochet hook, pass above the needle to catch the yarn.
Pass the starnd inside the loop to form a new loop. You casted on 1 stitch.
Replace the strand under the needle.
Repeat steps 3 and 4 until you have the desired number of stitches on the needle. Stop after the step 3 for the last casted on stitch.
With the crochet hook, catch the yarn and pass it through the loop to form a new loop. Repeat 3 to 4 times (= chain stitch).
Cut the yarn and pull it to loosen the last loop (but do not tighten the chain stitch too much).
Work the stitches with the yarn for your project then work the piece as indicated in the pattern.
Releasing the stitches from the corchet provisional cast on
Place your project in your left hand. With a needle, loosen the strand from the chain stitch.
Carefully pull the strand to loosen all the chain stitch.
Continue to pull carefully the strand to untie the 1st stitch. You can see the 1st loop make from your project yarn.
Pass the needle in this loop (= 1 st) as if you were purling it.
Finish to pull the scrap strand of yarn until you have removes it completely from the stitch on the needle.
Repeat step 2 until all the casted on stitches are untied and all the corresponding stitches (with your project yarn are on the needle. The scrap yarn pass through a loop on the border of your project.
Pass the needle through it : it is your last stitches. Remove the yarn. You should have as many stitches on your needle as you first casted on.
Work as indicated in the pattern.