Increases and decreases are used to shape knitted pieces. Increases make pieces larger; decreases make them smaller. For ease of working, increases and decreases are often worked on right-side rows either within the knitted piece or at the side edges. Here’s a summary of basic increasing and decreasing to shape a knitted piece.
Increasing
The simplest increase technique is the make-one increase (M1) which most knitters usually learn to do first. Because it makes an invisible increase, it’s very effective when making increases within the middle of a row or the body of a piece. To do this increase, with the needle tip lift the strand between the last stitch knit and the next stitch on the left hand needle and knit into the back of it. One knit stitch will have been added. At the beginning of a row, to increase you knit twice in the same stitch to form two distinct stitches.
Decreasing
By working a specific decrease, you can slant the stitches to the right by knitting two stitches together (k2tog) or left (ssk) by slipping the next two stitches knit-wise, one at a time, to the right hand needle, inserting the tip of the left hand needle into the fronts of these stitches from left to right; and knitting them together. One stitch has been decreased. This is valuable to know when working pieces with shaping such as raglan armholes, where the slant of the edge is important. When the slant is unimportant, you can work either type of decrease. But the k2tog decrease is simplest.
Use these techniques for adding or subtracting one or two stitches at a time. When increasing or decreasing several stitches, you will need to use casting-on or binding-off techniques.
