Hanham Variation

The Hanham Variation answers 3. d4 with 3...Nd7, defending e5 with a piece and preparing ...Ngf6, ...Be7 and ...c6 rather than conceding the center with 3...exd4. On d7 the knight cannot be harassed by d5 or pinned by Bb5, and if White exchanges with 4. dxe5, the most frequent reply in the database, Black may recapture with either piece or pawn, because the knight covers d8 and prevents a queen trade with check. The line takes its name from James Moore Hanham, who used it repeatedly at the Sixth American Chess Congress in 1889.

The critical reply is 4. Bc4, which aims at f7 and renews the threat of dxe5. The natural 4...Be7? fails to 5. dxe5 dxe5 6. Qd5, so the main defense is 4...c6, controlling d5. White can then choose the Schlechter (5. Nc3), Krause (5. O-O) or Delmar (5. c3), while 4...Nb6 is the Sharp Variation. Quieter is 4. Nc3 Ngf6, the Lion setup, and 4. c4 can lead into the Old Indian Defense. Engines give White a slight edge, though Black scores slightly better in online practice.