Primstav (or Runestav) are traditional Scandinavian calendar sticks dating back to at least the 12th century (and perhaps further). They are used to chart the Runic Calendar.
At the first full moon after midwinter solstice a new primstav is started to mark the beginning of the year and counts through a 7 day cycle (much the same as the Gregorian calendar) usually marked with runes to signify the weekdays (in the case of a runestav) or marked with images (for a primstav), such as the carved horn (in the last picture) that represents Julaften. The first image in the same picture is for the midwinter solstice.











