Modern Variation, Main Line

The pin 4...Bg4 stops the f3-knight from recapturing on e5 after ...dxe5, and it prepares ...Bxf3 to loosen White's hold on d4. The usual reply is 5. Be2, which breaks the pin and restores control of e5. In that line Black typically keeps the tension and develops within the space available: 5...e6 6. O-O Be7 7. c4 Nb6 8. Nc3 O-O. Releasing it with 5...dxe5 6. Nxe5 Bxe2 7. Qxe2 gives White an improved Larsen Variation, with Qb5+ hitting b7 among the ideas. Alburt, Kovačević and Bagirov championed the line, though at top level 4...dxe5 5. Nxe5 c6 has largely replaced it.

The Alekhine Variation, 5. c4, drives the knight to b6, since 5...Nb4 fails to Qa4+. After 5...Nb6, 6. Be2 is inaccurate because 6...dxe5 7. Nxe5 Bxe2 forces White to recapture with the king or give up the d-pawn, so 6. exd6 is played instead. 5. Bc4, 5. exd6 and the Panov, 5. h3, are less common. Engines give White a slight edge, but practical results are almost exactly level.