Pyhäjoki (Finnish Stitch 1+2½)

This stitch has been used in many places: 
Finland at least in South Carelia, Kymenlaakso, Pyhäjoki, Vimpeli, Tervola, Kannas) 
Sweden at least in Morkarla, Södermanland, and also known as Sorunda 1 stitch. 

Hansen's Notation
UOOo/uUUOO F1 (or F2)  (video)
small o ja u = split the yarn with the needle (ie. needle in between plies)