Crab Stitch is essentially a reverse single crochet. The texture and simplicity makes it ideal for a final border row on just about anything you can imagine. Also, it is not a stitch that can easily have any rounds or rows following it as it would create a generally messy appearance.
It is easiest to work a moss stitch into a round of single crochet to ensure more even stitch placement. It is possible to place moss stitch as the only border around a project if you prefer.
For this tutorial, I have made a simple square using HDC, using a medium (#4) weight yarn and an I/9 (5mm) hook. Then, I evenly single crocheted around the square, placing 3 stitches in each corner.
With the right side of your work facing you, join at the further left point (if you’re right handed) of your work using a slip stitch.
NOTE ... When working with a square or rectangle, I prefer to join in what will end up being my lower right hand corner. You can join anywhere you feel like works for your project.
Insert your hook into the next stitch to the right of your slip stitch used to join
Hook your working yarn and pull a loop through, being sure to stay to the left of the loop already on the hook
NOTE ... I don’t use a full “yarn over” in the above step as it creates a messy look. I just hook the yarn and pull up a loop
Yarn over and pull the loop through the two loops on the hook. Moss stitch complete.
Continue working each stitch to the right. If you have corners, do not increase. Rather, keep your tension a little looser in the corners to prevent pulling.