Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6

2...Nc6 is the natural move, combining defence of the pawn with control of the d4 square and avoiding committing another pawn for now.

White has multiple choices here which can lead to very different games.

• 3. Bb5 is the most played. White puts pressure on the knight defending the pawn.
• 3. Bc4 is quieter. Instead of attacking the knight, White chooses to target the weak f7 pawn.
• 3. d4 is aggressive. Subsequent play may result in a very open game.
• 3. Nc3 is the quietest common continuation.
• 3. c3, the Ponziani Opening, opens the white diagonal for the queen, allows for an eventual d4 pawn push, and controls d4 and b4 (possible plants by the black knight) at the expense of hemming in the knight.

a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h 3. Bb5   (Ruy Lopez) a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h 3. Bc4   (Italian)

a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h 3. d4   (Scotch) a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h 3. Nc3   (Three Knights)

a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h 3. c3   (Ponziani)

Some more uncommon moves:

• 3. Nxe5, the Irish Gambit, sacrificing a knight for a pawn.
• 3. g3?!, the rarely seen Konstantinopolsky Opening
• 3. Be2, a passive reply called the Inverted Hungarian Opening or Tayler Opening.
• 3. b4, a very rarely seen gambit called the Pachman Wing Gambit.
• 3. c4!?, Dresden Opening, not allowing d5 and after Nf6 transpose to Nimzowitch variation Nc3!, is not bad

a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h 3. Nxe5   (Irish Gambit)

a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h 3. g3   (Konstantinopolsky)

a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h 3. Be2   (Inverted Hungarian)

a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h 3. b4   (Pachman Wing Gambit)

a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h 3. c4   (Dresden)

Estimated next move popularity

Bb5 48%, Bc4 26%, d4 14%, Nc3 9%, c3 1%. All other moves less than 1%.

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

1. e4 e5 2. Nf3 Nc6

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Wikipedia has related information at King's Knight Opening

• Nunn's Chess Openings. 1999. John Nunn (Editor), Graham Burgess, John Emms, Joe Gallagher. ISBN 1-8574-4221-0.

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