knit 1 stitch front and back
Kfb or k1fb simply means knit stitch front and back. This is an increase stitch.
To work this stitch simply work a knit stitch like you would normally, except you don’t remove that old stitch off your left needle… keep it on there. Now we’re going to bring our right needle around to the back and insert our needle through that back loop and knit it, this time taking it off our left needle.
You’ll see we now have 2 stitches on our right needle from that original stitch!