Vienna Game: what should Black play?

In the Vienna Game position arising after White places a knight on d5, Black's only objectively sound response is Qxd5. Capturing the loose knight eliminates an immediate central threat and leaves Black with a slight advantage, evaluated at -0.70. Across 169,249 games recorded at this position, failing to take the piece results in an overwhelming disadvantage for Black.

The Decisive Capture with Qxd5

The move Qxd5 is essential because White has placed d5 on an undefended square. Capturing the piece directly nets material before White can consolidate. A continuation provided by the engine features Qxd5 c3 Nc6 Qb3 Be6 Qxd5, where Black smoothly develops minor pieces while White spends tempi exchanging queens. By converting the material immediately, Black avoids unnecessary defensive problems and secures the superior position.

Severe Alternatives and Missteps

Any candidate move other than the queen recapture leaves Black facing a decisive deficit of more than three pawns. Developing moves such as Nc6 (+3.66) or Be6 (+3.72) completely miss the opportunity to remove d5, allowing White to reinforce the outpost with pawns or develop comfortably. Similarly, pawn pushes such as f5 (+3.76) or h6 (+4.04) fail to address the tactical reality on the board. The massive evaluation gap between Qxd5 and all alternative replies makes this position an absolute single-move test for Black.