Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. c3/3...Nf6/4. d4/4...Nxe4/5. Bd3

White threatens Black's centralised knight.

Though Black can just defend it with 5...d4, the real point of this move is to develop White's kingside with tempo. This means that White can take the e5-pawn 6. Nxe5 Nxe5 7. dxe5, recovering the material, and answer 7...Bc5 (threatening to take on f2) with 8. O-O. Contrast with the line 5. Nxe5?! Nxe5 6. dxe5?? Bc5, where the threat to f2 is unstoppable.

5...Nf6?! allows 6. dxe5 to recover the pawn while gaining tempo on the knight.

5. Bd3 is an old move, played since the 19th century.^[1] It fell out of favour as 5. d5, kicking Black's knight, became the more popular choice.

However, 5. d5 allows 5...Bc5, the sharp Vuković gambit, which became dangerous for White in the 2000s after the continuation 6. dxc6 Bxf2+ 7. Ke2 Bb6! was discovered. 5. Bd3 avoids facing the gambit and so is safer. It is the engine-recommended fifth move.

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

1. e4 e5 2. Nf3 Nc6 3. c3 Nf6 4. d4 Nxe4 5. Bd3

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