Summary: We consider a 3-dimensional Riemannian manifold \(M\) with a metric tensor \(g\), and affinors \(q\) and \(S\). We note that the local coordinates of these three tensors are circulant matrices. We have that the third degree of \(q\) is the identity and \(q\) is compatible with \(g\). We discuss the sectional curvatures in case when \(q\) is parallel with respect to the connection of \(g\).