What Does psso Mean in Knitting
psso stands for "pass slipped stitch over." It's the second step of a two-part decrease — you've already slipped a stitch and knitted the next one, and now you lift the slipped stitch up and over the knitted stitch, dropping it off the needle. The result removes one stitch and creates a left-leaning decrease. If you've seen it written as sl1-k1-psso in an older pattern, this guide explains exactly how to work it and when it appears.
How to Work sl1-k1-psso Step by Step
- Slip 1 knitwise. Insert your right needle into the next stitch as if to knit, but don't wrap the yarn — just slide the stitch to the right needle. This twists the stitch slightly, which is intentional.
- Knit 1. Knit the next stitch on the left needle normally. You now have two stitches on the right needle: the slipped stitch behind, and the newly knitted stitch in front.
- Pass the slipped stitch over. Use your left needle tip to pick up the slipped stitch (the one further back on the right needle) and lift it up over the knitted stitch and off the needle entirely. One stitch decreased.
The result leans to the left — the knitted stitch sits on top, the slipped stitch goes under and behind it, creating a diagonal that runs toward the left. This is why psso decreases are used on the right-hand side of a V-neck or raglan where you want the decrease to lean toward the centre.
psso vs ssk — Same Result, Different Method
Older patterns (published before roughly the 1990s) typically use sl1-k1-psso as their left-leaning decrease. Modern patterns almost universally use ssk (slip, slip, knit) instead. Both create a left-leaning decrease that removes one stitch. The finished fabric looks nearly identical.
The technical difference: ssk re-mounts both stitches before knitting them together, which can produce a slightly neater result. sl1-k1-psso works the stitches in sequence and some knitters find it leaves a slightly looser decrease. In practice, the difference is minor enough that you can substitute one for the other in most patterns.
If you're working from a vintage pattern and it says sl1, k1, psso — work it as written, or substitute ssk with identical results.
sk2p — The Centred Double Decrease
sk2p stands for slip 1, k2tog, pass slipped stitch over. This is a centred double decrease that removes two stitches at once and creates a vertical ridge with stitches leaning equally to both sides. You'll find it at the centre of lace motifs, raglan lines worked from the top, and V-neck centres.
To work sk2p:
- Slip 1 knitwise.
- Knit the next two stitches together (k2tog).
- Pass the slipped stitch over the k2tog stitch and off the needle.
You started with 3 stitches and now have 1. The centre stitch of the original three sits on top, flanked by the others going behind on either side — creating a clean, centred line.
When psso Appears in Lace
In lace patterns, you'll often see psso as part of a double decrease used to balance a yarn over (yo). Since every yo adds a stitch, every decrease removes one — the net stitch count stays the same. A sl1-k2tog-psso (slip 1, k2tog, then pass the slipped stitch over) is a common lace double decrease that removes two stitches to balance two yarn overs nearby.
In lace, the direction the decrease leans creates the visual line of the pattern, so it matters which decrease you use. The pattern will specify — don't substitute unless you understand the visual effect.
Common Mistakes When Working psso
Slipping purlwise instead of knitwise. For psso, the slip should be knitwise. Slipping purlwise leaves the stitch untwisted, and when you pass it over, it can twist awkwardly or sit too loosely. The knitwise slip pre-positions the stitch correctly.
Passing over too loosely. When you lift the slipped stitch over, pull gently but snugly. Leaving the stitch loose makes the decrease look large and messy. After passing over, give a small tug on the working yarn to snug the new stitch down.
Losing your place in the sequence. If you stop mid-decrease and come back to it, check which stitches are on which needle before continuing. It's easy to confuse whether you've done the knit 1 yet.
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