Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...Nf6/4. Ng5/4...d5/5. exd5/5...Nd4/6. c3/6...b5/7. Bf1/7...Nxd5/8. Ne4/8...Qh4/9. Ng3/9...Bg4/10. f3/10...e4

=Two Knights Defence:Fritz variation=

9...e4
Hans Berliners move. This position has been the subject of World Correspondence Championship games. Black has the advantage in development but White has extra material in many lines. It seems White's position is better but finding the correct moves is not easy and many times Black comes out better.

Theory Table
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 * 1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Ng5 d5 5.exd5 b5 6.Bf1 Nd4 7.c3 Nxd5 8.Ne4 Qh4 9. Ng3 Bg4 10.f3 e4