Jaenisch Counterattack

The Jaenisch Counterattack, 3...Nf6, also called the Jaenisch Variation, is the most frequent reply to the Ponziani and the main alternative to 3...d5. It takes its name from Carl Jaenisch, who recommended it in a book of analysis published in 1842. The knight develops while striking at e4, exploiting the fact that 3. c3 has taken the natural defending square from White's queen's knight. White must decide at once whether to continue with the central plan regardless, protect the pawn, or let it go for development.

The usual answer is 4. d4, in keeping with the idea of 3. c3. Black may capture either central pawn, and in both cases White intends to push the remaining one with tempo and win back the material. After 4...Nxe4 5. d5 the attacked knight on c6 normally retreats with 5...Ne7 or 5...Nb8, while 5...Bc5, the Vukovic Gambit, abandons it for complications. Jaenisch himself analyzed both recaptures. After 4...Nxe4 5. dxe5 d6 6. Bf4 dxe5 7. Qxd8+ Nxd8 8. Bxe5 Bc5 the queens are gone early, and after 4...Nxe4 5. d5 Nb8 6. Bd3 Nf6 7. Nxe5 Bc5 8. O-O O-O 9. c4 d6 10. Nf3 Bg4 11. Nc3 Nbd7 Black has developed smoothly and stands comfortably. The other capture, 4...exd4, produces a more double-edged game.

The second most popular choice is 4. Bc4, the Neumann Gambit, in which White develops and leaves e4 hanging. The modest 4. d3 shores up the pawn but leaves the c3-pawn without much purpose and lets Black claim the center with 4...d5. 4. Bd3 is an occasional alternative. Besides 4. d4 and 4. d3, the engine also gives 4. Qa4, using the queen's diagonal that 3. c3 opened to pin the knight.

The line is regarded as Black's safest way of meeting the Ponziani, and its range of outcomes, from wild gambit play to rather passive and dry positions, makes it unappealing for a White player hoping for a set pattern. The engine rates the position as level. In Lichess games White scores only marginally better than Black, and draws are unusually rare.