Kennedy Variation

The Kennedy Variation arises after 1. e4 Nc6 2. d4 e5. Black sets aside the hypermodern restraint typical of the Nimzowitsch Defense and challenges the center immediately. The knight and the e-pawn both bear on d4, so Black threatens to capture there. White must choose between advancing the pawn, exchanging on e5, or supporting d4. The engine gives White a slight edge, and White scores somewhat better than Black in practice, though the margin is modest. It is one of the more frequently reached named positions in online play.

The most common reply, by a wide margin, is 3. d5, the Linksspringer Variation. White gains space and drives the knight from c6 to a less active square, usually 3...Nce7 or 3...Nb8. After 3...Nce7 4. Nf3 the e5 pawn needs further protection, so the knight moves again with 4...Ng6. The result is a fixed central structure in which White holds extra space and Black's pieces must work from behind the e5 pawn.

3. dxe5 releases the tension and often leads to exchanges. After 3...Nxe5 the quiet 4. Nf3 is the Paulsen Attack. Following 4...Nxf3+ 5. Qxf3, Black can offer the queen trade with 5...Qf6 and head for an early endgame. White has more ambitious tries in 4. Nc3, the Keres Attack, and 4. f4, which gains time against the centralized knight. Against 4. f4, Black can retreat with 4...Nc6, the Riemann Defense, or play 4...Ng6, which is designated the main line. Instead of recapturing on move three, Black can leave the pawn on e5 in several named gambits: 3...d6 (de Smet Gambit), 3...Bc5 (Bielefelder Gambit), 3...f6 (Hammer Gambit) and 3...Qh4 (Herford Gambit).

Defending the pawn with 3. Nf3 transposes to the Scotch Game, which is normally reached by 1. e4 e5 2. Nf3 Nc6 3. d4. Here White allows Black to capture on d4 and open the position. The rare 3. Nc3 leads to the Vienna Game: Fyfe Gambit, in which d4 is left to be taken. It is the only frequent continuation in which Black's results are better than White's.