Grünfeld Defense: Three Knights Variation, Petrosian System

Before the first move

The Grünfeld Defense is a dynamic, hypermodern opening where you allow White to build a large center only to strike back at it immediately. In the Petrosian System, White develops both knights and brings the dark-squared bishop to g5 to pressure your f6-knight, creating a sharp strategic battle over the d4 and c4 squares.

1. d4White

White starts with d4, the second most popular opening move. It immediately controls the center and prepares for a strategic battle. You will often see this lead to the Queen's Gambit, but here it sets the stage for your hypermodern counter-attack.

1... Nf6Black · your move

Develop your knight to f6. This flexible move prevents White from immediately playing e4 and keeps your options open for several defenses. It is the most common way to meet the queen's pawn, preparing to challenge the center with either d5 or a kingside fianchetto.

Other paths here: Na6 (Australian Defense) · g5 (Borg Defense: Borg Gambit) · b6 (English Defense) · e5 (Englund Gambit)

2. c4White

White plays c4, expanding their influence and challenging you to define your setup. While White could try the Tartakower Attack with g3 or the London-style f4, the c4 push is the most ambitious attempt to seize the initiative in the center.

Other paths here: f4 (Canard Opening) · g4 (Indian Defense: Gibbins-Weidenhagen Gambit) · e4 (Indian Defense: Omega Gambit) · d5 (Indian Defense: Pawn Push Variation)

2... g6Black · your move

Push your pawn to g6. You are preparing to fianchetto your bishop on g7, where it will exert powerful pressure along the long diagonal. This move signals your intent to play either the King's Indian or the Grünfeld Defense.

Other paths here: g5 (Indian Defense: Medusa Gambit) · b5 (Indian Defense: Pyrenees Gambit) · a6 (Indian: 2.c4 a6) · Nc6 (Mexican Defense)

3. Nc3White

White plays Nc3, increasing the pressure and daring you to strike. White has many alternatives here, such as the Anti-Grünfeld lines with f3 or h4, but developing the knight is the most principled way to fight for the center.

Other paths here: d5 (Indian Defense: Anti-Grünfeld, Advance Variation) · f3 (Indian Defense: Anti-Grünfeld, Alekhine Variation) · h4 (Indian Defense: Anti-Grünfeld, Basman-Williams Attack) · g3 (King's Indian Defense: Fianchetto Variation, Immediate Fianchetto)

3... d5Black · your move

Push your pawn to d5. This move defines the Grünfeld Defense. You are directly challenging White's center and inviting an exchange of pawns. If White captures, you will use the resulting open lines to launch an attack against their remaining central pawns.

Other paths here: Bg7 (King's Indian: 3.Nc3 Bg7) · c5 (King's Indian: 3.Nc3 c5) · c6 (King's Indian: 3.Nc3 c6) · d6 (King's Indian: 3.Nc3 d6)

4. Nf3White

White plays Nf3, entering the Three Knights Variation. This is more solid than the sharp Stockholm Variation with Bg5 or the Exchange Variation. White focuses on steady development before deciding how to resolve the tension in the center.

Other paths here: e3 (Gruenfeld: 4.e3) · g3 (Gruenfeld: 4.g3) · g4 (Grünfeld Defense: Gibbon Gambit) · f3 (Grünfeld Defense: Lutikov Variation)

4... Bg7Black · your move

Fianchetto your bishop to g7. Now your bishop is perfectly placed, eyeing the d4-pawn and the c3-knight. This piece will be your primary weapon throughout the game, often becoming the strongest piece on the board if the center opens up.

Other paths here: c6 (Gruenfeld: Schlechter, 5.Qb3)

5. Bg5White

White plays Bg5, the Petrosian System. By pinning your knight, White complicates your defense of d5. You'll need to choose between the sharp Ne4 jump or more solid responses to deal with this pressure on your key minor piece.

Other paths here: cxd5 (Gruenfeld: Three Knights Exchange) · g3 (Gruenfeld: Three Knights, 5.g3) · Qa4+ (Grünfeld Defense: Flohr Variation) · Bf4 (Grünfeld Defense: Three Knights Variation, Hungarian Attack)

Where you stand

The position is rich with tactical possibilities. White hopes to use the pin on f6 to maintain central control, while Black often responds with Ne4 to create immediate counter-threats. Both sides must balance their development with the looming pawn breaks in the center, particularly the potential trade on c4 or the push to e4.

• f6-e4 Jump the knight to e4 to break the pin
• g5-h4 Maintain the diagonal pressure if the knight moves
• e2-e4 Push e4 to seize full central control
• c7-c5 Strike at the base of White's center