Grünfeld Defense

The Grünfeld Defense arises when Black, having prepared a kingside fianchetto with 2...g6, plays 3...d5 instead of the King's Indian setup. The move contests the center directly and prevents an immediate e4. Black is not trying to hold a center of their own. The usual aim is to let White take it, then undermine it with the g7-bishop, ...c5 and piece pressure. The opening became a standard demonstration of the hypermodern view that a large pawn center can be a target. Ernst Grünfeld brought it into international play at Bad Pistyan in 1922.

The most frequent reply is the Exchange Variation, 4. cxd5 Nxd5 5. e4 Nxc3 6. bxc3. White gets a mobile c3-d4-e4 mass and attacking prospects on the kingside. Black answers with ...Bg7 and ...c5, often adding ...Nc6, ...Qa5, ...Bg4 and ...cxd4 to bear down on d4. The older approach for White was Bc4 and Ne2, castling and pushing f4-f5. From the late 1970s an early Rb1 became popular, taking the rook off the long diagonal. A newer scheme uses Be3, Qd2 and a rook to c1 or d1, sometimes preparing d5. Among fifth-move alternatives, 5. Bd2 avoids the doubled c-pawns, and 5. Na4, the Nadanian Variation, targets c5.

The Three Knights Variation, 4. Nf3, is the second most common choice. It keeps options such as 4...Bg7 5. Qb3, the Russian Variation, which pressures d5 and induces 5...dxc4 6. Qxc4 O-O 7. e4. Black then chooses among systems such as 7...a6, 7...Bg4 and 7...Na6. After 4. Nf3 Bg7, the quieter 5. e3 also occurs. The Brinckmann Attack, 4. Bf4, has a reputation as a safer route that keeps a smaller center and seeks queenside initiative. A common line is 4...Bg7 5. e3 c5 6. dxc5 Qa5, while 5...O-O instead offers the Grünfeld Gambit. The Stockholm Variation, 4. Bg5, is the most positional of the main tries. Rarer options include 4. f3 (Lutikov), 4. Qb3 and the Zaitsev Gambit, 4. h4.

Play is often sharp and heavily theoretical, with long forcing lines in the main branches. The engine sees the starting position as close to balanced, and Lichess results are nearly even, with Black scoring marginally better than White. Smyslov, Korchnoi, Stein and Fischer all played it. Kasparov used it in world championship matches against Karpov and against Kramnik in 2000, and Carlsen, Vachier-Lagrave, Svidler and Anand have played it more recently. The Byrne–Fischer "Game of the Century" of 1956 reached a Grünfeld by transposition.