A stitch from S.F.A. Caulfeild’s Dictionary of Needlework, pp. 130-131, rewritten in modern terms.
This is an open, netlike stitch with thick horizontal ridges.
A handsome raised stitch used for crossovers, petticoats, and comforters. It should be worked in double Berlin or four thread fleecy wool. Make a foundation chain of the width required, and work a row of Tricot, and then back. Second row–work the first stitch plain, then bring the wool in front of the work and put the hook into the hollow between the first and second loop, allow this to catch hold of the wool at the back, the wool passing from the front to the back over the work, bring the hook back again to the front with the wool on it, put it into the hole between the second and third loops, and let it catch the wool, returning with it on the hook, where there will now be three loops for the one stitch, draw the last made loop through the other two (see fig.248), and retain it on the hook. For the next stitch, put the wool forward, and the hook into the same space as before, between the second and third loops, and repeat from * [transcriber’s note: there was no *]. Work the last stitch as the first stitch, and work back in Tricot.
Work a row of regular TSS (the most basic stitch in Tunisian crochet), and work back.
Bring the yarn forward, in front of the hook.
Insert the hook into the space between the first and second stitches, bring the yarn over to the back, and pull a loop through.
There are now two new loops on the hook.
Insert the hook between the next two stitches, and pull a third loop through.
Pull that loop through the previous two loops.
*Yarn forward, insert the hook into the last space you pulled a loop through, and pull another loop through. Insert the hook into the next unworked space, pull a loop through, and pull the same loop through the previous two loops.* Work the last stitch as you would for Tunisian Simple Stitch, making sure to not pull it tight, as the Open Raised Tricot stitch grows vertically.