Morphy against Mongredien — the fourth game of their 1859 Paris match, a Two Knights' Defence.

1. 6.d3 This move is just mentioned en passant by Heydebrand, in the German “Handbuch.”
2. 7…Bg4 P. to K's 5th leads to a strong attack, and renders the defence difficult.
3. 9…Bd6 Bad; P. to K's 5th should have been played instead.
4. 17…g5 Exposing the King, at once, to a most formidable attack.