this is an example of the (in)famous brioche stitch.
its not a hard stitch to do… its just so weird, you’re sure it’s wrong at first!
You knit into stitch below, then pull the stitch above off the needle.
the stitch above will ‘run’ (ladder, drop, what ever you want to call it!)
ONLY it will only be able to run 1 row…down to the the stitch you just knit into!
the result is something like a slip stitch (since the stitch below is (row A) is now stretching up to current row (row C)… but the slip stitch as ‘wings’ (the undone stitch from row B) .
Have you ever seen a brioche? its a bun like bread with a bun in the top crust. this stitch is sort of like that.
the brioche stitch (knit into stitch below) can be worked many stitch patterns, and results in a whole bunch of named stitch patterns that utilize the effect.
when use in:
ribbing its called fisherman’s rib or shaker rib
in 'seed stitch" is callled beehive stitch
in stocking knit is called a brioche stitch
there are other combinations (half rib, (brioche stitch on right side, regular ribbing on wrong side) --i think there are about 30 different "patterns’ based on using the brioche stitch (exclusively or in combination with standard knits and purls)
the stitch is also used in with color work and can result in many radically different effects… in ribbing, you can get 2 toned ribs, or side A color A, side B color B ribs (reversible two toned knitting)
in the brioche stitch (worked in stocking knit) in 3 colors, it can end up looking like complex crochet
just follow the directions, (it will look weird the first row or two, but after a few rows, be prepared to be amazed!)