Rubuta ci gaba ga wannan sakin layi - Karpov yayi ƙoƙari 9...Nd7 sau da yawa a wasan 1990 na gasar zakarun duniya
, amma Kasparov ya sami fa'ida mai yawa a kansa a wasan na 18. Yana da ƙarfi amma dan kadan m. Rashin rikicewa 9...Nd7 kuma ana kiranta da bambancin Chigorin don haka akwai bambance-bambancen biyu na Ruy Lopez tare da wannan sunan, amma 9...Na5 shine motsi mafi yawanci da aka danganta da Chigorin. Wannan tsaron kuma an san shi da bambancin Keres, bayan Paul Keres.