Key ideas
- After 4.cxd5 exd5 5.Nf3 Nc6 6.g3, the Rubinstein System, Black usually ends up with an isolated queen's pawn on d5. The bishop on g2 presses on it, and the main line continues 6...Nf6 7.Bg2 Be7 8.O-O O-O.
- From there the Classical Variation branches with 9.Bg5, adding pressure on d5, and 9.dxc5, after which Black recaptures with 9...Bxc5 or plays 9...d4.
- Gambits appear on both sides. The Schara Gambit (4...cxd4) gives a pawn for quick development, and the Marshall Gambit (5.e4) is White's attempt to break the centre at once.
Plans for White
Blockade the isolated pawn on d4, pressure d5 with the g2 bishop, Bg5 and the rooks on the d-file, and aim to trade pieces, since the pawn grows weaker in an endgame.
Plans for Black
Use the open lines: develop actively with ...Be6 or ...Bg4, ...Re8 and ...Ne4, and look for the ...d4 advance or a kingside attack before White can simplify.
Watch out
Releasing the tension with ...c4 too early is risky. In the Swedish Variation, 4.cxd5 exd5 5.Nf3 Nc6 6.g3 c4, White answers 7.e4, striking at d5 before Black has castled.