 The 6-j symbol is the first representative, , of -"j" symbols that are defined as sums of products of of Wigner's 3-"jm" coefficients.The sums are over all combinations of that the -"j" coefficients admit, i.e., which lead to non-vanishing contributions.If each 3-"jm" factor is represented by a vertex and each j by an edge, these -"j" symbols can be mapped on certain 3-regular graphs with vertices and nodes.