chigorin made a number of contributions to the theory of chess openings. the most important were the chigorin variation of the ruy lopez (1.e4 e5 2.nf3 nc6 3.bb5 a6 4.ba4 nf6 5.o-o be7 6.re1 b5 7.bb3 d6 8.c3 o-o 9.h3 na5) and the chigorin defence to the queen's gambit (1.d4 d5 2.c4 nc6).