Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...Nf6/4. Ng5/4...Bc5/5. Nxf7/5...Bxf2/6. Kf1/6...Qe7/7. Nxh8/7...d5/8. exd5/8...Nd4/9. d6/9...Qxd6

9... Qxd6
At this point, White often prefers to play 10. Nf7. After 10...Qc5 11. d3, Black will be able to launch a strong attack on the White king, especially with an activated bishop pair after Bg4. White's strategy involves moving their king to safety on g1 at one point and trading off material. With perfect defense, Black can regain their disadvantage in material, but there is no forced checkmate.

10. c3 can also be played first with 10...Bg4 11. Nf7 but this is less concrete and likely favors Black. Additionally, 10...Bg4 11.Qa4+ leads to a perpetual check and draw with best play (see below).