The mirror partner of k2tog: at the beginning of a row, after a marker.
1. Slip two stitches one at a time to the right needle knitwise (needle goes in left to right): this reorients the stitches2. Return both to the left needle and knit them together through the back loops: the right needle goes in behind the left3. Ssk leans left, mirroring k2tog. Work it at the beginning of the row or after a marker
How to do it
Slip two stitches knitwise, one at a time.
Insert the left needle into the front loops of both.
Knit them together through the back loops.
Tip
The classic "slip, knit, pass over" (skp) gives the same lean but looks coarser.