Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...Nf6/4. Ng5/4...Bc5/5. Nxf7/5...Bxf2/6. Kxf2/6...Nxe4/7. Ke3/7...Qh4/8. g3/8...Nxg3/9. hxg3

9. hxg3
Black must be careful here. If 9...Qxc4, 10. Nxh8 and Black runs out of steam. If 9...Qxg3+, 10. Qf3 and the queens are traded. Therefore, 9...Qd4+ must be played first.