Key ideas
- The main line is 5...dxc4 6.Qxc4 O-O 7.e4, when White has an ideal-looking centre and Black must choose a way to attack it with pieces.
- 7...Bg4, the Smyslov Variation, develops while adding pressure on d4 through the pin on f3. After 8.Be3 Nfd7, Black plans ...Nb6 and ...Nc6, hitting the queen and d4. White chooses between 9.Qb3 and 9.Be2 Nb6 10.Qd3 Nc6.
- 7...a6, the Hungarian Variation, prepares ...b5 to gain time against the queen. 7...Na6, the Prins Variation, prepares ...c5 with the knight ready to recapture. 7...Nc6 and 7...c6 are other tries.
- White's centre is healthier than in the Exchange Variation, but the queen on c4 is exposed. Black's ...Nb6, ...Be6 and ...b5 ideas all gain time against it.
Plans for White
Develop with Be3, Be2 and Rd1, and keep the centre protected. A well-timed e5 or d5 can cramp Black's pieces. Move the queen to safety before Black's minor pieces gain tempi against it.
Plans for Black
Counter the centre with pieces: ...Bg4 and ...Nfd7-b6 hit d4 and the queen, while ...c5 or ...e5 opens lines for the g7 bishop. Every tempo gained against White's queen is valuable.
For the wider picture, see the Grünfeld Defense guide.