Passing a stitch over is how you decrease stitches by one
Passing a stitch over (often written as "psso" or "pass slipped stitch over") is a decrease that removes one stitch from your needle by pulling an existing stitch over the stitch next to it. You slip one stitch, knit the next stitch, then pull the slipped stitch over the knit stitch and off the needle. The result is one fewer stitch on your needle, and the decrease leans to the left on your finished fabric.
This decrease appears in many patterns—shawls, sweaters, socks, and lace designs all use it. It's one of the most common ways to shape your knitting, and once you understand the three-step motion, it becomes automatic.
Key Takeaways
- Pass slipped stitch over (psso) removes one stitch by slipping a stitch, knitting the next stitch, then lifting the slipped stitch over the knit stitch and off the needle.
- The decrease leans left on your fabric, which makes it useful for paired decreases on either side of a center line.
- You can slip the stitch knitwise or purlwise depending on the pattern, though knitwise is more common.
- The motion becomes smoother with practice, and you'll eventually do it without thinking about each step.
The three-step motion: slip, knit, pass over
Start with the stitch you want to slip sitting on your left needle. Insert your right needle into that stitch from left to right (knitwise), and slide it off the left needle onto the right needle without knitting it. You now have one slipped stitch on your right needle.
Knit the next stitch on your left needle in the normal way. You now have two stitches on your right needle: the slipped stitch and the new knit stitch.
Pick up the slipped stitch with the tip of your left needle. Insert the left needle through the slipped stitch from left to right, then lift it up and over the knit stitch and off the right needle entirely. The knit stitch stays on the right needle. You have decreased by one stitch, and the decrease leans to the left.
Why the decrease leans left
When you pass the slipped stitch over the knit stitch, the slipped stitch ends up on top of the knit stitch in the finished fabric. This creates a visible slant to the left. If your pattern calls for a left-leaning decrease on the left side of a shawl or a sweater front, psso is the right choice.
On the right side of a symmetric design, you would usually pair it with a right-leaning decrease (such as knit two together, or k2tog) to create a balanced V-shape or diamond. The two decreases mirror each other.
Slipping knitwise versus purlwise
Most patterns that call for psso expect you to slip the stitch knitwise—that is, from left to right as if you were about to knit it. This is the standard and the easiest motion.
Some patterns, especially lace patterns, specify slipping purlwise (from right to left, as if you were about to purl). Slipping purlwise twists the stitch slightly, which can change how it looks in the finished fabric. Always check your pattern to see which one it asks for. If the pattern does not specify, knitwise is the safe choice.
Common mistakes and how to avoid them
The most common mistake is knitting the slipped stitch instead of slipping it. This happens when you move too fast or forget the first step. Slow down for the first few times you work this decrease in a row, and say "slip, knit, pass over" to yourself as you do each step.
Another mistake is pulling the slipped stitch over too roughly, which can stretch it or split the yarn. Lift gently and deliberately. The stitch should slide over the knit stitch and off the needle smoothly, not with force.
If your decreases look uneven or loose, you may be pulling too hard on the working yarn after the decrease. Tighten the working yarn gently after you pass the stitch over, but do not yank it. Even tension comes with repetition.
When to use psso instead of other decreases
Psso and k2tog are the two most basic decreases, and they lean in opposite directions. Use psso when you need a left-leaning decrease. Use k2tog when you need a right-leaning decrease. For a centered decrease that does not lean, you would use slip, slip, knit (ssk) or centered double decrease (cdd).
In lace patterns, psso often appears because the slipped stitch creates a delicate, open look. In shaping (armholes, necklines, waist shaping), you choose psso or k2tog based on which side of the garment you are working and which direction you want the decrease to lean.
Practicing the motion until it feels natural
The first time you work psso, it will feel slow and deliberate. That is normal. Work through a few rows of a practice swatch, doing the decrease every other row or every few rows. Your hands will learn the rhythm, and you will stop thinking about each step.
If you find yourself hesitating or making mistakes, put the needles down and come back to it later. Knitting when you are tired or frustrated leads to errors. A few minutes of rest and then a fresh start often makes the motion click into place.
Frequently Asked Questions
What does psso stand for?
Psso stands for "pass slipped stitch over." It is a decrease that removes one stitch by slipping a stitch, knitting the next stitch, then lifting the slipped stitch over the knit stitch and off the needle.
Is psso the same as ssk?
No. Psso slips one stitch, knits one, then passes the slipped stitch over. Ssk (slip, slip, knit) slips two stitches, then knits them together through the back loop. Both are left-leaning decreases, but they are worked differently and can look slightly different in the finished fabric.
Can I use psso on the purl side of my fabric?
Yes. On the purl side, you purl the slipped stitch over instead of knitting it. Slip a stitch purlwise, purl the next stitch, then pass the slipped stitch over the purled stitch. The decrease will still lean left when viewed from the knit side.
Why does my psso decrease look loose or uneven?
Uneven tension is the most common cause. Make sure you are pulling the working yarn snug after the decrease, but not so hard that you distort the stitch. Also check that you are slipping the stitch without twisting it. Practice on a swatch until the motion feels smooth.
Do I need to slip the stitch knitwise every time?
Most patterns expect knitwise unless they specify otherwise. Slipping purlwise twists the stitch slightly, which changes its appearance. Check your pattern instructions. If none are given, knitwise is the standard choice.