What Does sl1 Mean in Knitting

You've hit sl1 in your pattern and you're not quite sure what to do with it. Sl1 means "slip 1 stitch" — move a stitch from your left needle to your right needle without working it. Simple in concept, but there are two ways to do it that produce very different results, and most patterns don't specify which they mean. Here's how to know which to use and when.

Knitwise vs Purlwise: Why It Matters

When you slip a stitch, you insert your right needle into it and move it across. But the direction you insert the needle changes the orientation of the stitch on the needle.

Slip knitwise (sl1k): Insert your right needle from left to right as if you're about to knit the stitch, then slide it across without wrapping the yarn. This rotates the stitch 180° — the stitch ends up twisted (sitting with its left leg in front of the needle instead of its right leg). When you later knit or purl this stitch, it comes out twisted.

Slip purlwise (sl1p): Insert your right needle from right to left as if you're about to purl, then slide it across without wrapping. The stitch moves to the right needle in exactly the same orientation it was sitting in on the left. It stays untwisted.

The default rule: Unless your pattern specifically says "knitwise," slip purlwise. In the vast majority of patterns, sl1 means sl1p. Slipping knitwise when the pattern means purlwise twists stitches that shouldn't be twisted.

Yarn in Front vs Yarn in Back

When you slip a stitch, the working yarn needs to be somewhere. Its position creates either a carried strand on the right side or wrong side of the fabric.

Yarn in back (wyib): Hold the yarn to the back of the work (away from you, on the "wrong side" if you're working a knit row). Slipping with yarn in back keeps the float on the wrong side — invisible from the front. This is what you want for slipped stitch edge stitches on the knit side.

Yarn in front (wyif): Hold the yarn to the front of the work (toward you). This puts a horizontal bar across the front of the slipped stitch — which is sometimes the effect you want (in certain stitch patterns), and sometimes a mistake you need to avoid.

For edge stitches on a purl row: slip purlwise with yarn in front (it's already there from purling). For edge stitches on a knit row: move yarn to front, slip purlwise, move yarn back before knitting the next stitch.

How sl1 Is Used in Decreases

The most common use of sl1 in decreases is in sl1-k1-psso (slip 1, knit 1, pass slipped stitch over). This is a left-leaning decrease — it's the traditional version of what modern patterns usually write as ssk.

Here it matters whether you slip knitwise or purlwise. In sl1-k1-psso, you slip the stitch knitwise — this pre-twists it so that when you pass it over, the resulting decrease leans cleanly to the left without an extra twist. This is one of the few cases where slipping knitwise is the correct choice.

The pattern will usually specify this. If it says sl1, k1, psso without clarifying, slip knitwise — it's the standard for that decrease.

How sl1 Creates Neat Edges

Slipping the first stitch of every row (rather than knitting or purling it) creates a smooth chain edge instead of a bumpy one. For patterns where the edges will be seamed together or picked up for a border, this makes a significant difference.

For a chain edge: slip the first stitch of every row purlwise, with the yarn in its working position (front for purl rows, back for knit rows). Do not slip the last stitch — knit or purl it as usual. This creates a neat, interlocked chain of edge stitches, one chain per two rows, which is ideal for seaming.

How sl1 Is Used in Heel Flaps

Sock heel flaps use sl1 extensively to create a reinforced, padded fabric. The typical heel flap instruction is: sl1, k1, repeat from across; turn, sl1, purl to end. Alternating slipped and worked stitches creates a thick, double-layered fabric that holds up to the friction inside a shoe far better than plain stockinette.

In heel flaps, slip the first stitch purlwise, yarn in back on knit rows, yarn in front on purl rows. The slipped stitches also create the chain edge you'll use to pick up stitches for the gusset — each slipped stitch gives you one chain, and you pick up one stitch per chain.

Tips to Remember

• Default: slip purlwise unless the pattern says knitwise.
• In sl1-k1-psso: slip knitwise.
• Yarn position (front or back) creates the float on that side of the fabric.
• Slipping edge stitches creates a chainlike selvedge — one chain for every two rows.

Related Articles

• What does psso mean in knitting
• What does tbl mean in knitting
• How to read a knitting pattern — intermediate guide

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