Chess Opening Theory/1. d4/1...d5

Closed Game D00-D69 Queen's pawn opening 2. c4 · Queens gambit 2. Nf3 · Zukertort variation 2. Bf4 · Accelerated London system 2. Nc3 · Chigorin variation 2. e4?! · Blackmar-Diemer gambit 1...d5 · Closed game 1...d5 is the classical approach to fighting for the centre: occupying it with pawns. 1...d4 takes some space for Black and opens a line of development for Black's queenside bishop. Contest the centre with pawns 1...d5 controls the e4 square, so preventing White from securing an ideal two-pawn centre and all the space it would control. White can play 2. e4?! anyway, if they like, but the important thing is they can't keep the pawn there. 2. e4?! is the Blackmar-Diemer gambit, which is considered dubious against best play. After 2...dxe4, White hopes to get a lead in development as compensation for the lost pawn. 2. c4, the Queen's gambit, is the mainline. This is a much better try for getting a big centre. White offers the flanking c pawn to Black. Its threat is positional: if Black takes the free pawn, their d-pawn is deflected from its duty controlling the centre. White can then secure a bigger share of the centre for themselves, and should have no trouble recovering the gambitted pawn down the road. Therefore usually Black declines the gambit in one of a number of ways. Develop a piece Because both colours' d-pawns are already defended by their queens, there is less potential for immediate threats and forcing moves in the Closed game compared to after 1. e4 e5. Therefore, there are a wider range of reasonable turn two options and games have many transpositional possibilities by different move orders. It is usually good to develop a piece when possible, so White may wish to start there. 2. Nf3 is the Zukertort variation. This is a flexible move: the knight was almost always going to go to f3, so White plays that move first. White retains the option of playing 3. c4 later (and 2...Nc6 3. c4 is the most common continuation), transposing into a Queen's gambit. Other lines include 3. Bf4, the London system, or 3. e3, the Colle system. 2. Nf3 is the main sideline in tournament play. 2. Bf4 is the Accelerated London system. This is the main club-level sideline. It is popular for its straight-forward plans that can be played against a variety of Black move orders. White prioritises developing the bishop so that they can play e3 to support the d-pawn without trapping the bishop behind the pawn chain. White must be conscious of their b2 pawn however, which is now weakened and a source of Black counterplay. 2. Nc3 is the Chigorin variation. This is an uncommon move because it prevents White from playing c4. Unlike 1. e4 e5 2. Nf3, here the knight gains no initiative on d5 because the pawn is already protected by Black's queen. After 2...Nf6, the main reply, this can lead to 3. Bg5, the Richter-Veresov attack, or 2. Bf4, the Rapport-Jobava London. Other sidelines 2. f4!? is the Mason Attack and is dubious. It controls e5 once more, with the f-pawn. This weakens the kingside and creates a permanent hole on e4. White then usually doubles down with 3. Nf3 and although this is not fully sound, it could be playable. 2. g4? is the Zürich Gambit. It gives up a free pawn to 2...Bxg4 and is very unsound. White usually follows up with Bg2 and Nf3, but the kingside is weakened and the gambit is mostly good with surprise value. Theory table 1. d4 d5 2 Queen's Gambit c4e6 equal Zukertort Variation Nf3Nf6 equal Mason Variation Bf4Nf6 equal Levitsky Attack Bg5h6 equal Chigorin Variation Nc3Nf6 equal Queen's Pawn Game e3Nf6 equal Blackmar-Diemer Gambit e4dxe4 -1 Amazon Attack Qd3 -1 Queen's Bongcloud Kd2?Nc6 -2 London System Main Base Position with ...d5 Bf4 equal References Closed Game Nunn's Chess Openings. 1999. John Nunn (Editor), Graham Burgess, John Emms, Joe Gallagher. 1-8574-4221-0. Modern Chess Openings: MCO-14. 1999. Nick de Firmian, Walter Korn. 0-8129-3084-3. fi:Shakkiaapinen/Peli/1. d4/1...d5