Tervaleppä is a fingering-weight version of the Alder socks. I made some other changes too, to give it a smoother sole and make it more suitable for wearing inside shoes.

Like the Alder socks, Tervaleppä is a chevron sock that takes advantage of the mechanics of chevron-knit fabric to shape the garment: instead of adding increases, we omit decreases in the stitch pattern to form the heel gusset.

The socks are knit toe-up, starting with a disappearing loop cast-on. Slipped stitches accentuate the decrease lines of the stitch pattern and draw attention to the construction of the gusset. These lines then flow seamlessly into the decreases at both sides of the back of the heel, and back into the stitch pattern on the leg. The cuff is made with a ribbed version of the stitch pattern used on the foot and leg of the sock.

Skills required:

Working small circumferences in the round
Decreases: k2tog, p2tog, ssk and centered double decrease
Disappearing loop cast-on (or any other method for cast-
ing on a very small amount of stitches in the round)
Lifted increases
Yarnovers, reverse yarnovers, and twisting them closed (by
knitting or purling a yarnover through back loop; or knit-
ting or purling a reverse yarnover through front loop.)
Short rows: wrap and turn method

(Helpful links for techniques are included in a References & Resources section.)