NÅLBINDNING (NEEDLEBINDING)
It's a technique common during the Viking Age, with which they created stitched fabrics with only one needle. In fact, it's more related to hooking than knitting, and is best suited for making circle-built clothes, such as hats, mittens or socks. The result is a sturdy interlaced fabric, made of knots, and can easily serve as base for further felting.