If you made it through my article about increases, you’ll be pleased to hear that the decrease situation is slightly more straightforward. Slightly.
It’s easier because there’s really only one way to make a decrease work: by knitting (or purling) multiple stitches together, to make one stitch. Other than the knitting or purling thing, the only difference is how the needle goes into the stitches, from which side and at what angle.
There are two things to consider: the direction/slant of a decrease, and the placement within a row/round.
A Big Huge Note
The method for working a decrease depends enormously on stitch mount. All of the following instructions assume that your stitches are mounted in the common North American/Western European manner: right-leg forward. If your stitches are mounted left-leg forward—i.e., combination style—then the instructions I give below, and those commonly given in North American and UK patterns, simply don’t work.
If your stitches are not mounted with the right leg in front on the needle, simply reposition them before you work these decreases.
K2tog and P2tog—knit or purl two stitches together—both lean towards the right. That is, you’re working into two stitches, pulling the leftmost of the two on top. This alignment gives the decrease its lean.
K2TOG: Knit 2 together.
P2Tog: purl 2 together.
The p2tog is deceptive: in the result, the right-most of the two purl bumps sits on top of the left-most, making you suspect that this might be a left-leaner. It’s not. If you look to the stitches below the purl bumps, you’ll see that the left-most of the stitches is still lying on top of the one on the right, again, giving it a right lean.
But either way, you’ll notice that you can barely see the stitch underneath the k2tog or p2tog. This is a Good Thing, which we will take advantage of later.
You can, of course, go big: k3tog, k4tog, etc. They all still lean to the right.
K3tog: knit 3 together.
To create tidy edges, we also need a decrease that leans to the left. That is, a decrease that takes the right-most of two stitches and places it on top.
In the knit family, there are two commonly used left-leaning decreases: SKP and SSK. There’s also a third, which is a bit of a cheat but entirely passable in some situations.
SKP is worked as follows: Slip 1 stitch knitwise, knit the following stitch, and pass the slipped stitch over the stitch just knit. In older patterns, or those published in the UK, you might see this written as “sl 1, k1, psso.”
SKP: slip 1, knit 1, pass the slipped stitch over.
SSK is worked as follows: Slip one stitch knitwise, slip a second stitch knitwise, return them to the left needle without twisting them, and knit them together through the back loop.
SSK: Slip, slip, knit 2 together through the back loop.
Sidebar: Which Way to Slip for SSK
There’s Discussion about this. Some knitters prefer to slip the second stitch purlwise. They feel that the resulting stitch lies flatter. It absolutely does: slipping the second stitch purlwise causes the lower stitch of the decrease to twist and tighten up. The reason that this is of concern is that if you work a line of SSK decreases every other round, it wiggles.
Compare them in this swatch: the line of decreases on the right, in the box, is created with the k2tog worked every other row. A lovely crisp line results. On the left, you see an SSK worked every other row. The line is not so crisp.
This occurs because the SSK can be a little loose, it can be a bit more stretched out than a k2tog.
There’s two possible fixes for this. The first is to work the SSK very tightly—only on the tips of the needles. Don’t let the stitch stretch out.
The second? Instead of adjusting how you work the SSK, you can also adjust how you work the stitch above the SSK—the stitch in the following row or round. This works particularly well if you’re working in the round.
For example, if you’re working a sock gusset or toe decrease, or a mitten closure, on the even rounds that sit between the decreases, work the stitch that sits above the SSK as a K-tbl (knit through the back loop). If you’re working a sleeve or something flat, this leaves you needing to work the stitch that sits above the SSK as a P-tbl (purl through the back loop).
Which solution works best for you depends enormously on how you knit, how you tension your yarn, the gauge of the fabric, the color of the yarn. Try them all!
SSK and SKP are utterly interchangeable. They achieve the same thing: a left-leaning decrease. Which you use depends entirely on which you find easier to do, and which you like the look of. It’s knitter’s choice: if you encounter either of these in pattern, use the one you prefer. Just be consistent.
The third left-leaning decrease is K2tog-tbl. Because it twists the stitch that lies on top, the resulting stitch is materially different.
Does it matter which one you choose? If you’re using a dark yarn, or the decrease isn’t particularly visible; if you’re not trying to pair it with a k2tog, if there aren’t so many of them that you’re worried about a possible minor tightening of the gauge, then it absolutely doesn’t matter.
And again, you can go big: Sssk and K3tog-tbl will decrease two stitches instead of one. A double decrease becomes a bit more complicated if you’re of the SKP school. More on which in another column.
Yes, there are also left-leaning purl decreases: there’s SSP and P2tog-tbl.
SSP: Slip one stitch knitwise, slip a second stitch knitwise, return them to the left needle without twisting them, and purl them together through the back loop.
P2tog-tbl: Purl 2 together through the back loop.
SSP is very tidy and perfect, p2tog-tbl results in a twisted stitch lying on top.
They’re both a bit annoying to work, which is why it’s better to work your shaping on the RS of your stockinette, in the knit stitches. If you do find yourself having to decrease in fabric that’s RS-purl facing, then you can work p2tog both at beginning and ends of rows without guilt—you won’t be able to see the lean, so don’t worry about it.
And you’ll notice I’ve provided no photos of these decreases because, as noted above for the p2tog, it’s hard to see the lean of the decreased stitches with a purlwise decrease.
Placement and Pairing
Working in Rows
“Decrease at the beginning and the end.”
The simplest answer is a k2tog in the first two and last two stitches of the rows, but it’s untidy and results in edges that are hard to seam.
The typical pairing is to place ssk at the start of the row/round, and k2tog at the end, as the slant of the decrease matches the slant of the edge.
I like this, I find it tidy and pleasing.
But there’s no reason why you couldn’t do it the other way, placing k2tog at the start and ssk at the end, for a more distinct, feathered line.
If the designer hasn’t been specific about the method, then it’s knitter’s choice.
If you’re working in rows, and the piece is going to be seamed, and you want tidy and unshowy decreases, work the decrease that is aligned with the edge, and one stitch in from the edges, e.g.
Dec row (RS): K1, ssk, k to last 3 sts, k2tog, k1.
This gives you a tidy selvage for the seam, and the decreases will sit against the seam.
If you want the decreases to be more visible, work them two stitches from the edge. And as before, you can choose to align them with the edge, as follows:
Dec row (RS): K2, ssk, k to last 4 sts, k2tog, k2.
Or work the even more visible “feathered” variation:
Dec row (RS): K2, k2tog, k to last 4 sts, ssk, k2.
Working in Rounds
If you’re working in rounds, I don’t suggest placing the decreases right next to each other. K2tog causes the fabric to pull right, and SSK/SKP causes it to pull left, and the tension created by working k2tog right before an SSK/SKP can cause distortion and misalignment of the fabric. It’s best to have a stitch or two between them, such as:
Decrease round: K1, ssk, k to last 2 sts, k2tog.
Decrease round: K1, ssk, k to last 3 sts, k2tog, k1.
In the lower half of this swatch, the decreases are placed right next to each other, and there’s a bit of a gap between them. Putting two stitches between the decreases makes it all smoother and tidier.
And of course, you can “feather” them if you prefer.
And Finally, the Meaning of “Fully Fashioned”
The term “fully fashioned” is used to describe knit fabrics in which the shaping increases and decreases are worked as part of the fabric. When knitting machines were first developed, they were only capable of making rectangles, with straight edges. Garments were made by cutting these pieces into the shapes required, as we do when we sew with machine-knit fabrics. Handknitters would ensure that the shaping of their pieces were visible, to distinguish their work from the (clearly inferior) machine-made.
Eventually, knitting machines got sophisticated enough to work shaping. Now you often see machine-knits with shaping so visible it borders on the absurd. Look at the armhole shaping of a commercially made sweater, and you may see some pretty bulky and showy decreases. It feels a bit defensive, if you ask me.