A virtual knot, which is one of generalizations of knots in R 3 (or S 3 ), is, roughly speaking, an embedded circle in thickened surface Sg × I. In this talk we will discuss about knots in 3 dimensional Sg × S 1 . We introduce basic notions for knots in Sg × S 1 , for example, diagrams, moves for diagrams and so on. For knots in Sg × S 1 technically we lose over/under information, but we have information "how many times a half of the crossing of the knot in Sg × S 1 rotates along S 1 ", we call it labels of crossings. In this paper we extend this notion more generally and discuss its geometrical meaning. This paper follows from [1].