1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0-0 Nxe4
In his classic work "The Modern Game of Chess" (1912), Siegbert Tarrasch praised the Open Variation, which gives Black a free game, as the best continuation against Spanish. Many players followed Tarrasch's advice, and in the late 20th century the always combative Viktor Korchnoj in particular was one of its most loyal supporters. In the 1978 World Championship match in Baguio and in 1981 in Meran, he challenged Anatoly Karpov's Spanish with 5...Nxe4. 14 years later it was Viswanathan Anand who put the Open Variation on the board against Garry Kasparov in the World Championship match in New York, but once too often, as he ran into the world champion's diabolical preparation in the tenth game of the match. With 4...Nf6 Black attacks the white e-pawn, the only difference to the Berlin Defence (3...Nf6) is that the moves 3...a6 4.Ba4 were slipped in. But this small detail is extremely significant, because Black can now shake off the pressure against the Nc6 at any time with ...b7-b5. After 5...Nxe4, 6.d4 b5 7.Bb3 d5 8.dxe5 Be6 has established itself as the main variation.
Based on this position, many rich systems have been developed for White and Black, the most important of which are 9.Nbd2, the classical 9.c3 and 9.Qe2, the Keres system. An example of how fascinating the game can be in these variations can be seen in a game. In 1978 Karpov led against Korchnoi after 9.Nbd2 Nc5 10.c3 d4
Igor Zaitsev's piece sacrifice 11.Ng5 in practice, which also happened in the Kasparov-Anand game mentioned above. This leads to interesting tactical complications.
The Open Variation is aptly named: the exchange of pawns in the centre leads to open, free play for the pieces, which is rich in tactical possibilities and at the same time strategically rich. For players with courage.