Double Crochet (dc)

This makes a more open fabric. The stitch is called a treble in the UK because of the three moves to make the stitch.

1. Wrap the yarn over the hook (yoh) from back to front, insert hook into next stitch, from front to back. Yoh again and draw through stitch.

2. There should be three loops on hook. Yoh and pull through two loops. Two loops on hook. Yoh. Pull through remaining two loops to complete.

Half-double crochet
The half-double is just that, half a double crochet, in step 2, pull through alt the remaining loops in one movement.