White threatens mate with 11.Qxh7# as well as 11.Bxb7 winning a bishop and a rook. After either 10...Ne4 11.Bxe4 or 10...Qxg5 11.Bxb7, Black loses the exchange, but obtains compensation in the form of one or more pawns and possibly a weakened white king. It is unclear if the position is a forced win for White.
Former world champion José Raúl Capablanca allowed 10.Ng5 twice in consecutive games as Black against Max Euwe in Amsterdam, 1931, drawing both times. The second game continued:[2]
The line has been played several times over the years at the highest levels, including Portisch–Andersson 1983,[3] which ended in a draw, and Aronian–Postny 2005,[4] which White won. The offer of the exchange has in fact been refused by White in grandmaster games (either by 10.Qxc3 or 10.Ng5 Ne4 11.Bxe4 Bxe4 12.Nxe4[5]).