Morphy Defense, Graz Variation

The Graz Variation, also known as the Graz Defense, arises when Black follows the Caro Variation 4...b5 5. Bb3 by bringing the king's bishop to c5, as in the Classical Defense. On c5 the bishop is more active than on e7 and bears down on f2. It is also a target for White's central advance c3 and d4, which can gain a tempo against it. With ...b5 already played, the Spanish bishop has been pushed to b3 before Black commits the g8-knight. The same position can be reached from the Classical Defense Deferred, 4...Bc5 5. O-O b5 6. Bb3.

White's two main replies are almost equally common. 6. O-O completes kingside development first, while 6. c3 prepares d4 at once. The quieter 6. d3 is a distant third. Engines give White a slight edge, and White scores somewhat better in online games. Alois Fink analyzed the line in Österreichische Schachzeitung in 1956 and again in Wiener Schach Nachrichten in 1979. It came into wider use only during the 1990s.