Advance Variation, Paulsen Attack

The Paulsen Attack arises after 1. e4 e6 2. d4 d5 3. e5 c5 4. c3 Nc6 5. Nf3 and is the principal line of the Advance Variation. With c3 already played, the knight on f3 becomes a second defender of d4 and also covers e5. White can then answer Black's pressure against the center by simply developing: a bishop to e2 or d3, castling, and in many lines a2-a3 followed by b2-b4 for queenside space. The quiet knight move also leaves the f-pawn at home, avoiding the problems on the g1-a7 diagonal that an early f2-f4 invites.

Black's aim is to pile up on d4 faster than White can consolidate. The usual reply, 5...Qb6, appears in nearly half of all games. The queen adds a third attacker and eyes b2, which makes the natural Be3 awkward. The play then hinges on White's sixth move. 6. a3 is the modern main choice, preparing b4. 6. Be2 is a calmer developing move, and 6. Bd3 gives up the d-pawn in the Milner-Barry Gambit. Against 6. a3, Black often answers with 6...c4 to fix the queenside, or with 6...Nh6, the Lputian Variation, routing the knight toward f5.

The Euwe Variation, 5...Bd7, is the main alternative and is chosen in roughly a fifth of games. Black develops the French bishop first and postpones the decision about the queen. The move has some strong advocates, and Black's results with it are comparable to those after 5...Qb6. The third most frequent move, 5...cxd4, releases the central tension at once. It is the least successful of the main replies for Black, with White scoring better against it than against either alternative. Engines also rate 5...Nge7 highly; from e7 the knight can reach f5, where it bears down on d4.

The resulting middlegames are mostly closed and maneuvering, built around the fixed pawn chain and the fight for d4 rather than early tactics. Theory is extensive in the 5...Qb6 lines, though both sides' plans follow clearly from the structure. The engine regards the position as roughly balanced, and online results are almost even, with Black marginally ahead.