What SSK Does and When to Use It

SSK stands for slip, slip, knit, and it is a left-leaning decrease that removes one stitch from your needle. You use it when a pattern calls for a decrease and you want the stitches to slant toward the left side of your work. SSK pairs with the knit two together (K2tog) decrease, which leans right—together, they let you create balanced shaping on both sides of a garment.

You will see SSK written in patterns as "ssk" or sometimes "sl 1, sl 1, k1, psso" (the older written-out version). It appears most often in shawls, sweaters, and anywhere the pattern needs a mirror-image decrease on the left and right edges. The decrease itself takes about three seconds once you know the motion.

Key Takeaways

  • SSK requires three steps in order: slip one stitch knitwise, slip another stitch knitwise, then knit those two slipped stitches together through the back loop.
  • The decrease leans left, making it the visual opposite of knit two together, which leans right.
  • You must insert your needle through the back loop of both stitches on the final knit step, or the decrease will lean the wrong direction.
  • SSK works the same on flat needles and circular needles, and the tension stays even if you keep your working yarn at the same tension as your regular knit stitches.

The Three-Step Motion for SSK

Start with your working yarn in the back, as if you were about to knit a stitch normally. Insert your right needle through the first stitch on your left needle from left to right, as if to knit. Slip that stitch onto your right needle without knitting it. Your right needle now holds one slipped stitch.

Repeat the motion with the second stitch on your left needle: insert your right needle knitwise and slip the stitch to your right needle. You now have two slipped stitches sitting on your right needle, and your left needle has moved forward two stitches.

Now comes the critical step. Insert your left needle through both slipped stitches from left to right, going through the back loop of each stitch. This is the move that creates the left lean. Knit these two stitches together as one. You have decreased by one stitch, and the decrease slants left.

Why the Back Loop Matters

When you knit two stitches together through the back loop instead of the front, you twist the stitch in a way that makes it lean left. If you forget this step and knit through the front loop instead, your decrease will lean right—the same direction as K2tog—and your shaping will look unbalanced.

The back loop insertion is straightforward to forget because it is the opposite of how you normally knit. Your instinct will be to insert the needle the "normal" way. Mark this moment in your practice: insert through the back loop, not the front. After a few rows, the motion becomes automatic.

Common Mistakes and How to Avoid Them

Forgetting to slip knitwise. If you slip the stitches purlwise (from right to left) instead of knitwise, the stitch orientation changes and your decrease will not lean the correct direction. Always slip knitwise for SSK.

Knitting through the front loop on the final step. This is the most common error. You will create a right-leaning decrease instead of a left-leaning one. Slow down on that final insertion and remind yourself: back loop, not front.

Pulling too tight after the decrease. SSK stitches can look loose if your tension jumps. Keep the same tension on the yarn as you would for a regular knit stitch. The decrease itself does not need extra tightening.

Confusing SSK with SKP. SKP (slip, knit, pass slipped stitch over) is an older decrease that does the same job as SSK. Both create a left-leaning decrease. SSK is easier to execute and is now the standard in modern patterns, so use SSK unless a pattern specifically calls for SKP.

Practicing SSK on a Swatch

Before you work SSK into a real project, practice on a small swatch using worsted-weight yarn and size 8 or 9 needles. Cast on 15 stitches and knit 4 rows in garter stitch (knit every row). On row 5, knit 3 stitches, work one SSK, knit to the end. Repeat this decrease every other row for 6 more rows.

Look at your swatch from the front. The decreases should form a clear diagonal line leaning to the left. If the line leans right instead, you are knitting through the front loop on the final step. If the stitches look twisted or uneven, you may have slipped purlwise instead of knitwise. Keep the swatch and use it as a reference when you start a real project.

SSK in Pattern Context

In a typical sweater pattern, you will see SSK paired with K2tog on opposite sides of the garment. For example, a raglan armhole decrease might read: "K2, K2tog, knit to last 4 stitches, SSK, K2." The K2tog on the right side leans right, and the SSK on the left side leans left, creating a balanced V-shape.

When you work these decreases row after row, the visual effect is a clean, symmetrical line of shaping. This is why the back loop step matters so much—without it, both decreases would lean the same direction and the shaping would look lopsided.

Frequently Asked Questions

Can I use SSK on circular needles?

Yes. SSK works exactly the same way on circular needles as on straight needles. The only difference is that you are working in the round instead of back and forth, but the stitch itself does not change. Slip knitwise twice, then knit through the back loop.

What if I slip the stitches purlwise by accident?

Your decrease will still work, but it may look twisted or lean the wrong direction. If you notice this after a few rows, you can frog back and redo those rows, or you can continue and learn from the mistake on your next project. Most knitters slip purlwise by accident at least once.

Is SSK the same as SKP?

Both create a left-leaning decrease, but the method is different. SSK is easier and is the standard in modern patterns. SKP (slip, knit, pass slipped stitch over) is an older technique that works but requires an extra step. Use SSK unless your pattern specifically asks for SKP.

Why does my SSK look loose compared to the rest of my knitting?

You are likely pulling the yarn too tight after the decrease, which creates a gap. Keep the same tension you use for regular knit stitches. If the stitch still looks loose, check that you are inserting through the back loop on the final knit step—the correct insertion creates a tighter stitch naturally.

Can I use SSK on every row?

Yes, but most patterns space decreases out over several rows to avoid a jagged edge. A typical pattern might decrease every other row or every third row. Check your pattern for the exact spacing, as it affects the slope of your shaping.