Blo stands for “back loop only.” This is a direction for where you should work the indicated stitch. Single crochet back loop only (or sc blo) indicates that you should insert your hook under the back loop only, not under both loops, when working your next single crochet.
What is a back loop crochet?
When you hold the piece of crochet in front of you with the Vs on top, the part of the V closest to you is the front loop. The part of the V farther away from you on the opposite side is the back loop.
What is the top loop in crochet?
The front loop is the top loop of a stitch that is nearest to you when you hold your work. In crochet patterns you will come across instructions like front loop only (flo), this means you insert your hook into this loop only.
What does NB mean in crochet?
NB: st + its yarn over counts as one, so knit together next 3 loops (or 2sts) P purl stitch. P1B: purl one below, insert needle through centre of stitch below next stitch on needle and purl in the usual way, slip the stitch above off the needle at the same time. P2tog: purl two stitches together.