A stitch from S.F.A. Caulfeild’s Dictionary of Needlework, p. 122, figure 221, rewritten.
This one reminds me more strongly of sewn smocking than the other Tunisian smocking stitches I’ve seen. (Though I am still new to this! So who knows what I’ve missed?) I also keep seeing the Greek letter pi in the stitches, which amuses me very much.
* * repeat the instructions between these until the end of the row.
YU yarn under; that is, bring the yarn forward under the hook, then wrap it around the hook.
TPS Tunisian purl. This video by Kim Guzman shows the maneuver:
TPS2tog instead of working the purl through one vertical bar, work it through the next two bars as if they were one bar.
TSS Tunisian simple stitch, also known as afghan stitch.
Make the foundation row as usual.
1. Work the first stitch as usual. *YU, TPS2tog* Work the last stitch as usual, and then chain back.
2. Work the first stitch as usual. TSS. *TPS2tog, YU* TPS. Work the last stitch as usual and then chain back.
Repeat these rows as desired.