This post is about single crochet (sc in patterns). This is the “US” term we use for this stitch. This same stitch is called double crochet (dc in patterns) in the UK. Always make sure you know which version the pattern means!
(This tutorial starts on the second row. Refer to the Insert Hook post
for ways to work into a base chain. When working into a base chain, ignore the instructions here for "turning chain" and work your first stitch into the 2nd chain from your hook.)
First, we need a “turning chain”. This is perhaps a poorly named maneuver because you’re not always going to use it to turn. This chain is used entirely to get the hook to the right height to match the stitch you’re about to do.
The standard turning chain for single crochet is “chain 1″. This is the only time the turning chain doesn’t count as a stitch.
This is what patterns are expecting you to know. If they want you to do this differently, the pattern will say so explicitly.
So, chain 1:
Since the turning chain for a sc doesn’t count as a stitch, you’ll want to work your first sc into the first stitch available. (Again, the pattern will say otherwise if the designer wants you to do something else).
Insert the hook in the first stitch and grab the yarn (yarn over)
And pull the loop through so you have two loops on the hook:
Make sure all loops make it onto the shaft of the hook, otherwise you’ll end up crocheting very tightly and unevenly.
Grab the yarn again (yarn over)
and pull it through both loops on your hook:
Continue in the same manner for the rest of the single crochet stitches:
insert hook, yarn over, pull through (2 loops on hook), yarn over, pull through both loops. Done.
Generally speaking, single crochet is used when you want a dense fabric, and is the primary stitch used when making amigurumi
(cute little crocheted dolls). Sc is also commonly used when making a ribbed fabric, by working the stitches into the back loop only. You might also see this stitch used for shaping and in lace.
When making a flat fabric with this stitch, it is common for the corners to curl. If you’re using a natural fibre yarn, you can usually block the piece and the curling goes away. Acrylic yarn will usually sort itself out in the wash. You can also avoid this issue by crocheting more loosely (by using a bigger hook), or adding a border.