Chess Opening Theory/1. d4/1...Nf6

Black controls e4 while developing a knight. This is the most flexible response to 1. d4. Black doesn't commit a pawn to the centre yet. They may yet do so, or they can fight for the centre in the hypermodern way: controlling it from afar with pieces, allowing White to construct their pawn centre but undermining it later with timely pawn advances.

This move gives White lots of leeway to either develop pieces or take more space in the centre. Openings tend to be flexible with lots of potential for transpositions.

White would like two pawns in the centre if possible.

2. c4 is the mainline: White takes more space and controls the important d5 square. After 2. c4, White can develop their knight behind their pawn line and perhaps play e4. Black can still choose to contest this centre with pawns with 2...d5, 2...c5 (Benoni), or 2...e5 (Budapest), but more typically they move their pawns only as necessary to develop their bishops: 2...e6, 2...g6, 2...d6 or 2...b6.

White can't play e4 and keep the pawn there (2. e4?! is called the Omega gambit and loses a pawn to 2...Nxe4). White can prepare 3. e4 with 2. Nc3 or 2. f3, which usually compels Black to play 2...d5 to keep control of e4.

Alternatively, White can prioritise piece development.

2. Nf3, the Knights variation is the chief sideline. It's a flexible move: White may still play c4 afterwards but first gets more information on how Black intends to play.

2. Nc3, prevents c4 but, as noted above, prepares e4. After 2...d4 (controlling e4) the main continuations are 3. Bg5, the Richter-Veresov attack, or 3. Bf4, the Jobava-Rapport London.

The bishop has two main candidate squares to develop to.

2. Bg5, the Trompowsky attack, pressures Black's knight. White has hopes of trading it to double Black's pawns.

2. Bf4 plays the Accelerated London system into Black's Indian defence. Play may transpose with 2...d5, but the Indian defence has original ways to meet it without ...d5.

• 2. e3 plays in Colle system-style against the Indian defence. Transposes if Black plays ...d5.
• 2. g4, the Tartakower attack, prepares to fianchetto the bishop.

• 2. d5?!, the Pawn push variation. Since Black didn't play d5, White can advance their pawn, guarded by their queen. After 2...e6 3. dxe6 fxe6, White loses their central pawn.
• 2. f4?!, the Canard opening.
• 2. Nd2?!, hoping to support e4 without preventing c4, should be met with 2...d4, but 2...e4?! is the unsound Lazard gambit.
• 2. g4?!, the Bronstein gambit, hopes to tempt Black's knight away from controlling e4 by offering a free flank pawn.

For explanation of theory tables, see theory table and for notation, see algebraic notation.

1.d4 Nf6

Estimated next move popularity: c4 62%, Nf3 28%, Bg5 5%, Nc3 2%, g3 1%, e3 1%, Bf4 and other moves less than 1%

• Nunn's Chess Openings. 1999. John Nunn (Editor), Graham Burgess, John Emms, Joe Gallagher. ISBN 1-85744-221-0.
• Modern Chess Openings: MCO-14. 1999. Nick de Firmian, Walter Korn. ISBN 0-8129-3084-3.

• Kasparov, Garry, & Keene, Raymond 1989 Batsford chess openings 2. ISBN 0-8050-3409-9.