Purl 2 together through the back loop (p2togtbl or p2tog tbl) is a 1-stitch decrease often used on the wrong side of your fabric or in a purl section on the right side of your fabric (such as in a purl column of ribbing).
This decrease leans to the left, which is barely noticeable on the purl side. If you look at the reverse side of a p2tog tbl, it looks just like a k2tog tbl (knit 2 together through the back loop), which also leans to the left.
Watch this video to learn how to p2tog tbl in both the Continental style and English style.
How to P2tog tbl
- Bring your yarn forward between the needles (just like you do for a purl stitch)
- Insert your right needle through the back of the 2nd stitch from below the stitch, then through the back of the 1st stitch, bringing your right needle tip in front of the left needle
- Wrap the yarn counter clockwise around the right needle and pull it through the 2 stitches (this is just like doing a regular purl)
- Slide the 2 stitches off your left needle
Now look at your p2tog tbl. Notice at the base of your new stitch there are 2 stitches. These 2 stitches are drawn together with the rightmost stitch in the front of the leftmost stitch. This is what makes this decrease lean to the left. The right stitch is in the front and is being pulled leftward toward the center.
Do not mistake the direction of the line formed when you repeatedly do decreases for the lean direction. The lean of a decrease is solely determined by how the stitches come together in the decrease, as described above.
These photos show the front and back of p2tog tbl (click on them to enlarge them):
Other Similar Decreases
Many experts claim that the backside of a p2tog tbl looks like a SSK (slip slip knit). Though they look similar, they do not match exactly. The SSP (slip slip purl) exactly matches the SSK, and the p2tog tbl exactly matches the k2tog tbl.
Both the p2tog tbl and the SSP lean to the left. On the reverse side of the fabric, they lean to the left just like k2tog tbl and SSK. The difference is that the “tbl” stitches twist the stitches and the ssp and ssk do not.
It is a subtle difference, so you could generally substitute one for the other. Likewise for k2tog tbl and SSK. You can compare them in the photo below. I find the SSP and SSK are slightly neater because the stitches are not being twisted.
Want to Practice p2tog tbl?
This stitch, as well as several other less common increases and decreases, is used in the beautiful Idril sweater. The lessons in our Idril Knit Along guide you step-by-step through the pattern. Check it out at https://knitalongclub.com/course/idril/.