In the UK, we have three different ways to explain a yarn over: yarn forward (yfwd), yarn over the needle (yon), yarn round the needle (yrn).
Basically these versions all do the same thing: they make a new stitch by taking the yarn over the right needle. The different names depends on which stitch comes before or after. So if you're making a stitch between two knit stitches, it's called yarn forward. The other two terms are used if you're making a new stitch between two purl stitches, between a knit and a purl stitch or between a purl and a knit stitch. I can never remember in which situation yrn or yon is used and I know many other knitters struggle with this too.
When you knit the continental way, these terms are even more confusing because we hold the yarn in a different way to English knitters and it's especially confusing if you use the Norwegian purl rather than the standard continental purl
Americans seem to use yarn over to cover any situation when you take the yarn over the right needle to make a new stitch and I quickly decided to adopt this approach. So I use yarn over any time I make a stitch by taking the yarn over the right needle. So instead of using yfw, yon, yrn, I use yo (for yarn over).
How you work the yarn over depends on your knitting style and which stitch comes before and after the yarn over. The yarn over is only 'taking the yarn over the right needle'. The stitch before or after is not part of the yarn over.
So let's look at a few examples. I'm assuming you're using either the English style or continental style of knitting.
Yarn over between two knit stitches:
- Your yarn is at the back because you knitted the previous stitch.
- If you knit the English style or purl the regular continental way, your yarn will be at the front after purling a stitch.
- If you purl the Norwegian way, your yarn will be at the back after purling a stitch.
- Your yarn will be at the back because you've just knitted a stitch.
- If you are an English style knitter or use regular continental purl, the yarn will be at the front after the purl stitch.
If you find this all a bit confusing, I've recorded a video to show you what I'm talking about. The video can also be viewed here.
In my patterns I use yarn over (yo) instead of yarn forward (yfwd), yarn over the needle (yon) or yarn round the needle (yrn) but many British based designers and British publications still use these terms instead of yarn over and that can be confusing. Every pattern should have a list of abbreviations which should explain each abbreviation.
If you have any questions, do ask me and I'll do my best to help.