It is well known that a non-singular real plane projective curve of degree five with five connected components is separating if and only if its ovals are in non-convex position. In this article, this property is set into a different context and generalised to all real plane separating (M-2)-curves.

• 14P25 - Topology of real algebraic varieties
• 51M15 - Geometric constructions in real or complex geometry