Knitting Decreases & Increases: Master SSK, K2tog, M1

October 10, 2026 / Marie

At a Glance

K2tog (knit 2 together) is a right-leaning decrease and the fastest to execute.
SSK (slip, slip, knit) is a left-leaning decrease; it is used to create symmetry with the K2tog.
M1 (make one) is an increase created by picking up the strand between two stitches without leaving a visible hole—available as M1L and M1R depending on the desired lean.
The choice between these techniques is not about preference, but about the desired final result: the symmetry of a raglan, the seamless look of an armhole, or the openwork effect of lace.
Confusing an M1 with a yarn over, or an SSK with a K2tog, won’t change your stitch count, but it will completely change the look of your finished piece.

Are you following a pattern and came across “SSK,” “K2tog,” or “M1” without knowing exactly how to do them? These are the three most common techniques used for shaping in knitting: two decreases that remove a stitch from the row, and one increase that adds one. On paper, they seem similar—just one stitch more or less—but they produce very different inclinations and visual results once worked into the fabric. This guide details the exact movements for each, the visual differences they create, and most importantly, when to use which: for raglans, V-necks, armholes, hat crowns, or lace patterns.

Why Decreases and Increases Aren’t Interchangeable

Flat knitting—like a scarf or a rectangle—requires no shaping: the number of stitches remains the same from the first row to the last. However, as soon as a shape appears—an armhole curving inward, a V-neck tapering, a hat crown closing, or a sleeve widening—you must remove or add stitches at specific points in the row without breaking the continuity of the stitch.

This is where the choice of technique becomes critical. A decrease always removes a stitch, but it can lean the result to the right or to the left. An increase always adds a stitch, but it can either leave a visible hole (useful for lace) or remain completely invisible (ideal for solid garments). Following a pattern without understanding this logic often results in a garment with the correct stitch count but asymmetrical decreases, or an accidental eyelet appearing where it wasn’t intended.

Decreases: Removing a Stitch with Control

K2tog: The Right-Leaning Decrease

K2tog stands for “knit 2 together.” It is the simplest decrease to execute: you insert the right needle into the next two stitches at the same time, as if you were working a standard knit stitch, and knit them together. The result is a single stitch that visibly leans to the right on the right side of the work.

This decrease requires no prior manipulation of the stitches; it is a direct, quick movement that doesn’t slow down your knitting rhythm. For this reason, it’s often the first decrease beginners learn and is found in almost every pattern for shaping armholes or necklines.

SSK: The Left-Leaning Decrease

SSK stands for “slip, slip, knit.” You slip one stitch onto the right needle without knitting it, slip the next stitch the same way, then insert the left needle into these two slipped stitches to knit them together. This technique produces a stitch that leans to the left.

The SSK requires one more step than the K2tog, which is why some knitters underuse it or mistakenly replace it with another K2tog. The problem: on a symmetrical garment—both sides of a raglan, both sides of a V-neck, or both armholes of a cardigan—replacing an SSK with a K2tog breaks the symmetry. Both decreases then lean in the same direction instead of mirroring each other, and the eye immediately perceives the imbalance even if the knitter can’t explain why.

Double Decrease: Removing Two Stitches at Once

When a pattern asks to remove two stitches in a single decrease—typical for centered decreases in hat crowns or certain lace motifs—a double decrease is used (such as Sl2-K1-P2sso). The general movement involves slipping stitches and passing them over a knit stitch. The result is a centered decrease, where the slipped stitch remains visible above the knit stitches, providing a cleaner look than simply repeating K2tog twice in the same row.

Why Lean Matters as Much as Stitch Count

A garment is rarely shaped on only one side. On a sweater knit flat, each armhole has a left and right side; on a raglan, four lines of decreases rise in parallel from the armpits to the neckline. In these cases, the pattern intentionally alternates K2tog and SSK so that the decreases mirror each other: those on the left lean toward the center, and those on the right do the same, creating a symmetrical chevron effect rather than a series of stitches all leaning in one direction. Always check if the pattern specifies “K2tog” or “SSK” before decreasing to avoid having to rip back several rows once the asymmetry is noticed.

Increases: Adding a Stitch With or Without a Hole

M1 (Make One): The Invisible Increase

M1 stands for “make one.” The principle: between two existing stitches, there is a horizontal strand of yarn, invisible to the untrained eye. You slide the tip of the needle under this strand to lift it onto the needle, then knit it like a regular stitch. Because the new stitch is created from a strand already tensioned between two stitches—rather than added to the side of an existing stitch—it leaves no visible hole once the row is complete.

This technique comes in two versions depending on how the needle is inserted:

M1L (make one left): the strand is lifted from front to back, then knit through the back loop. The result leans to the left.
M1R (make one right): the strand is lifted from back to front, then knit through the front loop. The result leans to the right.

The difference isn’t obvious on a single isolated stitch, but it becomes clear when placed in mirror images—typically on either side of a widening raglan line or on both sides of a sleeve worked from the cuff up. Using an M1L where an M1R was intended simply reverses the direction of the twist: the garment keeps the correct stitch count but loses the symmetry the pattern intended to create.

The Yarn Over (YO): The Decorative Increase

A yarn over (YO) consists of wrapping the yarn over the right needle before knitting the next stitch, without inserting the needle into any existing stitch. Unlike the M1, the yarn over intentionally creates a hole; this is the foundation of all eyelets and lace patterns. An isolated yarn over, without a corresponding decrease to compensate, increases the total stitch count of the row; in a lace motif, it is almost always paired with a decrease (often a K2tog or SSK) elsewhere in the row so that the stitch count remains stable while creating the openwork pattern.

Confusing a yarn over with an M1 on a row that should not be openwork is one of the most visible mistakes in knitting: a small hole appears where the garment should be solid, right in the middle of an armhole or sleeve.

KFB (Knit Front and Back): The Simplest Increase

A third method, often noted as “KFB” or “increase 1,” consists of knitting into the same stitch twice without slipping it off the left needle: once normally, and then a second time into the back loop of the same stitch before letting it drop. This technique leaves a small horizontal bar visible just below the new stitch—a useful marker for counting increases in a row, but a detail to keep in mind if the pattern explicitly asks for an invisible increase; in that case, the M1 is preferable.

SSK vs. K2tog: The Most Common Confusion, Resolved

The question comes up in almost every search on this topic: why have two different decreases if they both remove only one stitch? The answer is entirely about the lean. The K2tog leans to the right because the two stitches are knitted together in their original position on the needle. The SSK leans to the left because the stitches are slipped first—which changes their orientation on the needle—before being knitted together.

On a plain piece of knitting without symmetrical shaping, the difference is negligible: both techniques remove a stitch and the visual result is almost imperceptible in isolation. However, it becomes decisive when a pattern shapes a garment symmetrically, which covers the majority of wearable projects: sweaters, cardigans, hat crowns, and triangular shawls. In these cases, systematically replacing SSK with K2tog for ease of movement results in a piece that looks correct in terms of size but is visually unbalanced, with all decreases leaning the same way instead of mirroring each other.

Reading Pattern Abbreviations: Quick Lexicon

Patterns often mix different abbreviations, especially when translated. Here are the most useful equivalents to ensure you use the correct movement:

K2tog = Knit 2 together (decrease, leans right).
SSK = Slip, slip, knit (decrease, leans left).
M1, M1L, M1R = Make one / Make one left / Make one right (invisible increase).
YO (yarn over) = Yarn over (openwork increase, creates a hole).
Sl2-K1-P2sso = Double decrease (removes two stitches, centered).

Identifying these abbreviations before starting a shaping row—rather than in the middle of it—prevents the most common error: starting the movement of one technique after reading the abbreviation for another.

When to Use Which Technique: Concrete Examples

The choice between these techniques rarely follows a single rule; it depends on the area of the garment and the desired look.

On a raglan, the four shaping lines run diagonally from the armpits to the neckline: patterns almost always alternate SSK and K2tog so that the decreases converge visually toward each dụng raglan line rather than heading in inconsistent directions.

On a classic armhole knit flat, decreases are generally worked a few stitches in from the edge rather than right at the edge to leave a small margin for easier seaming; the lean follows the same symmetry logic as the raglan, with each side of the armhole leaning toward its own center.

On a V-neck, a progressive central decrease on each side of the center stitch shapes the point: here again, alternating SSK on one side and K2tog on the other keeps the V symmetrical, whereas using the same decrease on both sides would result in a visibly off-center neckline.

On a hat crown, decreases are distributed around the round rather than concentrated on two lines; K2tog alone is usually sufficient, as the regular distribution around the circle dilutes the leaning effect that would be distracting on a straight line.

On a sleeve shaped from cuff to shoulder, invisible increases (M1L and M1R) are preferred over yarn overs because the result must remain solid and discrete; a yarn over is only used if the pattern intentionally includes an openwork detail on the sleeve.

In lace patterns, the yarn over is the standard: it creates the desired eyelet motif and is almost always associated with a decrease in the same row to compensate for the stitch count.

Common Mistakes and How to Spot Them Early

The first mistake is confusing the stitch count with the final look: simply counting correctly does not guarantee a symmetrical shape if the wrong decreases or increases were used. While recounting the total stitches after each shaping section is useful, it doesn’t replace a visual check of the lean in areas that are meant to be symmetrical.

The second mistake is confusing a yarn over with an M1: a small hole appearing outside of a lace section almost always signals this confusion and can only be fixed by ripping back to the affected row.

The third mistake is skipping the “slip” step in the SSK out of habit from the faster K2tog movement: the result has the correct stitch count but leans the wrong way—a flaw that often only becomes apparent once the piece is finished and laid flat, when it is too late to fix without ripping back several rows.

Placing a removable stitch marker at every point where a decrease or increase should occur before starting the row allows you to verify the movement at the right spot rather than discovering the error later while recounting.

Conclusion

Mastering these few movements is enough to cover the vast majority of shaping found in patterns for sweaters, cardigans, hats, and shawls. The difficulty is never in the complexity of the movement itself—each is repeated identically once learned—but in the habit of checking exactly which abbreviation the pattern requires at that specific spot. Using needles suited to your stitch and a ball of yarn with consistent tension will make these techniques much easier to repeat without error from one row to the next.

Sources: The technical movements described in this article have been verified via Studio Knit and tin can knits for Anglo-Saxon techniques (K2tog, SSK, M1L/M1R), and Lili Comme Tout and Les Triconautes for corresponding French terminology.

FAQ

What is the difference between SSK and K2tog?

Both remove one stitch, but K2tog leans to the right while SSK (slip, slip, knit) leans to the left. Patterns alternate them to create symmetrical decreases, for example, on either side of a raglan or a V-neck.

What does M1 mean in a knitting pattern?

M1 stands for “make one,” which is an invisible increase: you lift the strand of yarn located between two stitches and knit it, adding a stitch without leaving a visible hole.

What is the difference between M1L and M1R?

M1L leans to the left because the strand is lifted from front to back before being knitted; M1R leans to the right because the strand is lifted from back to front. The choice depends on which side of the garment the increase should mirror.

Can I replace an SSK with a K2tog?

On a plain project without symmetry requirements, the difference is subtle. On a symmetrically shaped garment (raglan, V-neck, armholes), systematically replacing SSK with K2tog makes all decreases lean the same way, breaking the mirror effect intended by the pattern.

Is a yarn over the same as an M1 increase?

No: a yarn over intentionally leaves a hole and serves as the basis for lace stitches, while a make one (M1) adds a stitch invisibly. Using a yarn over instead of an M1 creates a small hole where the garment should remain solid.

How can I tell the direction of a decrease once it’s knitted?

A right-leaning decrease (K2tog) shows the top stitch slightly shifted to the right; a left-leaning decrease (SSK) shows it shifted to the left. Comparing both sides of a symmetrical piece helps you spot an inversion quickly.

What is a double decrease and when should I use it?

A double decrease removes two stitches in one operation by slipping a stitch, knitting the next two together, and passing the slipped stitch over. It is mainly used for centered decreases, such as the top of a hat crown or in certain lace motifs.

Should I always follow the exact technique indicated in the pattern?

Yes, whenever the pattern shapes a piece symmetrically. A decrease or increase that adds or removes the correct number of stitches but in the wrong direction produces a garment that is technically correct in count but visually unbalanced when worn.