Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bb5/3...Nd4/4. Nxd4/4...exd4

Bird's defence Bird's defence C61 4...exd4 Black completes the knight trade. 5. O-O is the main move, after which Black has two main approaches: 5...Bc5, developing the kingside and supporting the advanced pawn, or 5...c6, gaining tempo on the bishop and supporting 6...d5 to expand in the centre. A sideline is 5. Bc4 first, putting the bishop on a more threatening diagonal while preventing ...c6 from gaining tempo. This lines sets some traps for Black. If they successfully navigate it, it normally results in the trade of some more minor pieces. Theory table 5. O-O Bc5 6. d3 c6 7. Ba4 Ne7 8. f4 f5 9. Bb3 d5 Bird's defence + 5. ... ... 6. ... ... 7. Bc4 d5 8. exd5 cxd5 9. Bb5+ Bd7 5. ... c6 6. Bc4 Nf6 7. Re1 d6 + 5. ... a5 6. d3?? c6 7. Bc4 b5 -- 5. ... Ne7 Paulsen variation 5. Bc4 Nf6 6. O-O Nxe4 7. Bxf7+ Kxf7 8. Qh5+ g6 9. Qd5+ Kg7 10. Qxe4 + References See also Ruy Lopez