Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Nc3

Three knights game C46 King's Knight Opening 3. Nc3 · Three knights game White prioritises development of their knights, sticking to the maxim to develop "knights before bishops," with the idea that they will always want to place Nc3 and Nf3, so why not play those moves first? Black usually develops their knight next, too, and the best place for that is 3...Nf6, entering the quiet but respectable Four knights game. This is by far the main line: while White's move didn't make any threats, it is surprisingly forcing simply because none of the ways to break symmetry are very appealing. If Black would like to develop their bishop instead, there isn't a great place for it right now: 3...Bc5 allows 4. Nxe5, the centre fork trick. Black's knight was not really defending the e5 pawn because after 4...Nxe5 5. d4! wins back the material with a fork. Black isn't down material, but it's a small positional mistake. 3...Bb4 is playable, but it may be too early because White can play 4. Nd5. This move is best reserved for after White's d-pawn has moved and the bishop would pin the knight. Black may consider fianchettoing it instead: the sideline 3...g6 is called the Steinitz variation and prepares ...Bg7, but is slow comparing to playing ...Nf6 now and waiting to develop the bishop along the a3 to f8 diagonal in one move later. Another sideline is the audacious 3...f5?, the Winawer defence. Black gambits the f-pawn. The mainline is 4. d4, but even taking the pawn 4. exf5 should be winning for White, though Black has some practical chances in amateur games. History The instruction, "knights before bishops", originates from Emanuel Lasker, who wrote (emphasis added)Lasker Emanuel Lasker's Manual of Chess The Theory of the Openings David McKay Company Philadelphia 1947: I have added to these principles the law: Get the Knights into action before both Bishops are developed. The advantage obtained in following this law is certainly not great, yet it is distinctly perceptible. In its full form, ("before both bishops") it is clear that he was not dismissing continuations where one knight and one bishop are developed first (the Italian game, etc) as unprincipled. Theory table 1. e4 e5 2. Nf3 Nc6 3. Nc3 3 4 5 Four Knights Game ...Nf6 d4exd4 Nxd4Bb4 = ...Bb4 Nd5Ba5 Bc4 +/= ...Bc5 Nxe5Nxe5 d4Bd6 +/= ...g6 d4exd4 Nxd4Bg7 +/= Winawer Defense ...f5 Bb5fxe4 Nxe4Nf6 +/= References See also Three Knights Game