“…However, a measure of game refinement can be employed to assess the degree of game sophistication. From the early studies using game refinement measure it is supposed that the history of chess variants may be divided into the three stages: the origin with moderate complexity and refinement, many diverging variants with high complexity and low refinement, and the modern sophisticated chess with low complexity and high refinement (Cincotti, H. Iida, & Yoshimura, 2007) (Iida, Takeshita, & Yoshimura, A metric for entertainment of boardgames: its implication for evolution of chess variants, 2003).…”