Brioche rib double decreases
This week's Knitworthy pattern, Opari, includes some rather tricky but very pleasing reversible double decreases. If you've never done any brioche knitting before the hat is a great project to get started with, and I've just issued an update with a few more clarifying notes to help you out, but if you're a visual learner you might want to look at a tutorial such as this one.
Rearranging the stitches
The stitches are arranged in an alternating pattern but in order to have a double decrease that looks the same on each side (although in opposite colours) we need to rearrange the stitches. This means that three MC ribs can be decreased into one and, on the following round, three CC ribs can be decreased into one. The MC decrease will be knit and the CC decrease will be purled.
It's easiest to use a cable needle but if you're comfortable cabling without one then you might not need it for this.
The 'br' indicates that this is a brioche decrease — there will be yarn overs paired with some or all of the stitches involved. The general rule is to always treat the yarn over and stitch as a single unit.
The 's2kp' is the abbreviation I use for a knit centred double decrease. It stands for: slip 2 stitches together knitwise, knit 1, pass the slipped stitches over the stitch just worked. Other than the yarn overs this is worked in the standard way.
This is the purl version of the previous decrease which requires a little more manipulation in order to avoid twisted stitches.