Knit 2 together through the back loop (k2togtbl or k2tog tbl) is a left-leaning 1-stitch decrease. Learn how to knit it and how it compares to other decreases in this tutorial.
Slip slip knit (ssk) is a common 1-stitch decreases in knitting that leans to the left. If you look at the reverse side of an ssk, it looks just like a ssp (slip slip purl), which leans to the right. This decrease is often used opposite k2tog to create symmetrical shaping. Learn how to ssk in this tutorial.
Slip Slip Purl (ssp) 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). It is knit similarly to the ssk, and there are 2 ways to correctly knit a ssp. In this video, I’ll show you both ways, focusing on the one I like best.
Purl 2 together (p2tog) is a decrease that is often used on the wrong side of the fabric, or on the right side in a purl section (such as in the purl column of ribbing). It is just like purling normally, except you work in 2 stitches at the same time. Learn how to knit p2tog, what it looks like, and other similar stitches in this tutorial.