Many times, a sweater or hat pattern will start at the bottom and work its way up. This means that the piece will need to be shaped to fit the smaller and larger parts of the body. When narrowing a piece of knitting, one uses a decrease of some kind. These are somewhat more difficult than increases of several factors.
It’s important to make sure that stitches aren’t simply dropped off the needle, which will unravel part of the fabric. (Again, this can be deliberately used repeatedly to create a pattern with lovely results, but it’s not something that you want to do willy-nilly.) Once cast on, every stitch needs to be anchored to the piece. If narrowing is needed, one or more stitches essentially need to be bound off in some way. When this is done to individual stitches, it causes the fabric to move directionally; in other words, the decrease maneuver will cause the resultant stitch to lean either to the right or two the left. This is why it’s important to learn different ways of decreasing, and to use the appropriate ones to make sure your fabric has the appropriate symmetry. Usually, patterns will use what are called ‘paired decreases’; this means that you use one kind of decrease on one side, and a different one of the other. In this way, the slant of the stitches fits the edge it’s one, and the shaped fabric looks balanced.
The easiest decrease is called a ‘knit two together’, or ‘k2tog’, and it is again exactly as it sounds: the needle slides into two stitches at a time, knitting them together as one. This decreases by one stitch; it’s also possible to ‘knit three together’, often seen as ‘k3tog’, or to twist the stitches by knitting them to the back of the loop instead of the front, usually abbreviated as a ‘k2togtbl’. For any of these, the number of stitches decreased generally be one less than the number of stitches manipulated – a ‘k2tog’, for example, creates one stitch where there were two earlier. This creates a right-leaning decrease.
To decrease with a stitch that leans to the left, slip both stitches to the right-hand needle as if to purl. Now, from this new position, knit them together through the back loop. This will reverse the direction of the resultant stitch, causing the lean to move to the left.
Another common decrease is uses what’s called a ‘pass over’, usually abbreviated as a ‘psso’. This usually involves slipping a stitch to the other needle without knitting it, knitting the next stitch, and then passing the slipped stitch over the second in the same way that you cast off. This decrease can also be combined with other maneuvers, such as a ‘sl 2-knit 1 – psso.’ This usually creates a left leaning decrease, but the slant isn’t as noticeable as it is with the previous maneuver.
As always, it’s important to practice these before actually using them. Read the directions in the pattern several times over to make sure you can visualize what you are going to do. If you can’t figure them out on your own, visit your local yarn shop and ask for some instruction. Most shop owners will be happy to help. (It doesn’t hurt to make a purchase while you’re there!)