This stitch is made up of a 4-row repeat.
You will need 2 hooks in order to complete the cable:
1 Tunisian hook
1 regular hook (this one is just to help hold stitches, so it can be any size so long as it is smaller than the Tunisian hook.
RP: Yarn over and pull through one loop on your hook (the first loop on the hook). Now yarn over, pull through two loops (loops 2 and 3 on your hook). Continue to yarn over, pull through two loops until you have only one loop on your hook.
KS: Insert your hook in between both threads of the second vertical stitch from your hook. Pull up a loop.
PS: Reverse yarn over (loop the yarn in front of your hook) and hold the loop down on your hook with your index finger. Insert your hook into the stitch, and release the reverse loop, and lay the yarn in front of the stitch. Yarn over, and pull up a loop.
Cast-on a foundation row:
Insert your hook into the second chain from hook. Yarn over, and pull the hook out of the stitch. You should now have two loops on your hook.
Go to the next stitch, insert your hook into the stitch and yarn over, then pull up a loop. You’ll now have three loops on your hook. Insert your hook into the next stitch, yarn over, and pull up a loop. You’ll now have four loops on your hook. Continue adding loops to your hook until you have cast on one loop for every stitch of your chain.
Complete a RP.
Row 1: PS, PS, KS into the next 6 stitches, PS, PS, KN into the last stitch of the row.
Complete a LP.
Row 2-3: Repeat Row 1.
Row 4: PS, PS, Skip 3 stitches and KS into the following 3 stitches. Use your regular hook: KS the 3 skipped stitches onto the regular hook, then slip those loops onto the Tunisian hook. PS, PS, and KS into the last stitch of the row.
Repeat Rows 1-4 until you complete the length you want for your cable.
Bind-off: Finish the last RP for the last row of your project, then insert your hook into the second stitch of the row (as if you were working a KS), pull up a loop and single crochet (yarn over and pull the loop through the two loops on your hook, so that you are left with just one loop on your hook). Repeat until you have crocheted one single crochet for every stitch of the row.