Rubinstein Variation, Blackburne Defense

The Blackburne Defense is the main branch of the Rubinstein Variation. With 4...Nd7, Black delays ...Nf6 by one move so that the other knight can go to f6. If White trades on f6, Black recaptures with a piece, avoiding both the doubled pawns of ...gxf6 and the early queen exposure of ...Qxf6. The related 4...Be7 follows the same idea with the bishop as the recapturing piece. Once the minor pieces are out, Black looks for the ...c5 break against d4. Among stronger players 4...Nd7 is the most frequent choice at this point.

White most often answers with 5. Nf3, which accounts for about two-thirds of games. The usual sequence is 5. Nf3 Ngf6 6. Nxf6+ Nxf6, after which White picks between 7. Ne5, the Capablanca Line, and 7. c3, the Kasparov Attack. 5. Bd3 and 5. c3 are less common alternatives, and engines also rate 5. Be3 highly. The engine gives White a slight edge, but Lichess results are almost evenly split between the two sides.