Tunisian Reverse Stitch and Variants

Tunisian reverse stitch and variants all work the back vertical bar from the wrong side of the fabric.

Tunisian Reverse Stitch (Trs)

From behind fabric, insert hook from behind back vertical bar.
YO and draw up a loop.

Purled Reverse Stitch (Ptrs)

Bring yarn to front of fabric then with the hook on the back side of the fabric, insert hook behind back vertical bar .
YO and draw up a loop.