Vienna Gambit, Paulsen Attack

The Paulsen Attack, 5. Qf3, is the most direct of White's fifth-move options against the centralized knight in the Vienna Gambit. The queen adds pressure to e4, threatening Nxe4 followed by dxe4 and Qxe4 to win a pawn. It also covers the check on h4 that Black's queen threatens once the f-pawn has advanced. Wikibooks rates it as White's best move in the position, but Black still has a route to equality or can enter unclear play with chances for both sides. The engine likewise judges the game roughly balanced.

The most frequent answer, 5...Nxc3, solves the problem by exchanging the attacked knight, and White's results after it are good. Black scores better with replies that keep the knight on e4. The Bardeleben Variation, 5...f5, props it up with a pawn at some cost to the kingside. The developing 5...Nc6 instead turns against the e5-pawn. Both of these are among the engine's preferred choices, along with 5...Be6, which reinforces d5. In every branch the play turns on White's e5-pawn and half-open f-file against Black's active pieces, and it stays sharp.