Crochet Techniques: Invisible stitch decrease

There are several ways to decrease  crochet stitches:
1. The easiest: skip one stitch of the previous row. This method leaves the front loop of the skipped stitch on display…
2. Insert the hook into next stitch (of previous row) – use only front loops of the stitches – and draw up a loop; insert the hook into the next stitch and draw up a loop. Yarn over, draw through all 3 loops on the hook. This method adds half of single crochet stitch, one vertical thread of single crochet stitch, so it is still visible.
3. As invisible as it can get:
Insert the hook in the front loop of the first stitch:

 do not yarn over, point the hook down in order to insert in the next stitch; insert the hook in the front loop of the next stitch ( three loops on the hook) :

 yarn over and pull the yarn through the first two loops; now you have two loops on the hook:

 Yarn over and pull through the remaining two loops on the hook to complete this stitch decrease: