Equivalence classes of normal form games are de ned using the geometry of correspondences of standard equilibrium concepts like correlated, Nash, and robust equilibrium, or risk dominance and rationalizability. Resulting equivalence classes are fully characterized and compared across di erent equilibrium concepts for 2 2 games. It is argued that the procedure can lead to broad and gametheoretically meaningful distinctions of games as well as to alternative w ays of viewing and testing equilibrium concepts. Larger games are also brie y considered. Keywords Non-cooperative games, classi cation and equivalence classes, experimental games, geometry of games. JEL Classi cation C 7 0 , C 7 2 , C 7 8 , C 9 0 , C 9 1 .