Single purl decreases are used far less often than single knitted decreases. Last week I said that we use SSK on the right side and k2tog on the left side. I wanted to clarify that you can do anything you want–and how you place your paired decreases is completely up to you. I do think it is good to know common practice or “the rules” and then you can decide if you want to break them. I think rules should always be broken if you have a good reason.
Single Purl Decreases
Why are they less familiar to us? We do most of our shaping on the right side while knitting. This is easier for most knitters. I think I became familiar with purl decreases when I started doing lace that is patterned on each row. Otherwise, we mostly avoid decreasing while purling, or on the wrong side.
P2tog is pretty well known to us. It is easy to do, and I would bet most knitters, outside of lace knitters, don’t even think of it as being directional.
P2tog-b / p2tog-tbl is the logical pairing, because it is left-leaning while p2tog is right-leaning. Like k2tog-tbl, p2tog-b/p2tog-tbl is not the most commonly used purl right-leaning decrease outside of lace. In shaping, most patterns use an SSP, a logical pair to SSK.
In the photo you may have a hard time finding the decreases on this side. I think that says everything we need to know about purl decreases. They are hard to find, so not a lot of attention is paid to them!
Single Purl Decreases on the Right Side
Let’s take a look at what these decreases look like on the knit side. There is virtually no difference between the SSP (the bottom decrease) and the p2tog-b. In how I executed them I think that I slightly favor the SSP for similarity to the p2tog. If I was doing the decreases in lace I would use the p2tog-b because it is quicker, but you might not find it so.
Single Purl Decreases and Their Knit Pairs
We’ve determined that SSP or p2tog-b is the left-leaning single purl decrease, so if executed on the right side, it would be at the beginning/right side, leaning toward the center. That means that the logical right-side pairing with the knit single decrease, would be the SSK. The p2tog is the right-leaning single purl decrease and would be paired with the k2tog as it’s knit counterpart on the RS.
Let’s say you were making armhole decreases and wanted to do decreases every row to shape your curve. On the SSK decrease side, you would want to do the decrease that would go in the same direction as the SSK on the right side, which is the SSP or p2tog-b. Makes sense, except that now you would be doing the SSP at the end of the row, not at the beginning. The k2tog gets paired with the p2tog, which is now done at the beginning of the row.
Memorization Trick for Single Purl Decrease
As I wrote this my brain started to knot. All of my logic is of little use to me in quickly deciding which single purl decrease to do. This is how I remember it:
- Where I SSK on the RS, on the WS I do an SSP or p2tog-b;
- Where I k2tog on the RS, on the WS I do a p2tog.
SSK=SSP and k2tog=p2tog
The other little trick I use is:
A p2tog, like a k2tog, is super easy to execute;
An SSK and SSP (or p2tog-b) are the more difficult to execute.
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