Help me solve a knitting mystery?

Hi, I need your help. I started this Afghan probably close to 20 years ago and, for some reason, abandoned it when it was just a few blocks away from completion. The pattern book has since gone missing. All I have to go on, is a scrap of paper with my knitting notes. It appears I was keeping track of each row I went. I have these letters written down in groups of four:

Obviously, K is knit, and I think I remember enough that KB is knit in the stitch below. But I don’t remember what I meant by bk. Can you help me figure out a likely answer going on this info in the photo I’ve attached? It would be hugely appreciated! It’s such a shame that I didn’t just finished the thing back when I started it, as it’s nearly complete and in surprisingly decent shape for my amateur skills.

Many thanks in advance!

Welcome to KH.
Guessing: it might mean knit through the back loop (k tbl) or it’s a transposition and should be kb. I’m always transposing things.

It looks like the Bee stitch. Instead of starting off with a knit stitch you start the row with knit one below. HTH

Thank you!! Very helpful! Appreciate the quick replies.