King's Indian: 5.Nf3 Bg4

King's Indian: 5.Nf3 Bg4

Definition

“King’s Indian: 5.Nf3 Bg4” refers to a specific branch of the King’s Indian Defense (KID) that arises after the moves 1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 Bg4. Instead of the more common 5…O-O, Black immediately pins the knight on f3 with the dark-squared bishop. The variation is also known as the Smyslov System (or sometimes the Karpov–Smyslov line) because of its early adoption by former world champions Vassily Smyslov and Anatoly Karpov.

Typical Move-Order

1. d4 Nf6
2. c4 g6
3. Nc3 Bg7
4. e4 d6
5. Nf3 Bg4

From here, the most frequent continuations are 6.Be2, 6.h3, or 6.Qb3.

Strategic Ideas

• Pressure on d4 and e4: By pinning the f3-knight, Black undermines White’s central control, making …e7-e5 or …c7-c5 easier to prepare.
• Flexible pawn breaks: Black often keeps castling in reserve and can choose between …O-O, …Nc6, …Nbd7, …c5 or …e5 depending on White’s set-up.
• Exchange plans: If 6.Be2, Black may exchange on f3, doubling White’s pawns and leaving the e5-square less protected (e.g., …Bxf3 Qxf3 Nc6 …e5).
• Avoiding main-line theory: The move sidesteps massive Classical KID theory beginning with 5…O-O 6.Be2 e5, making it attractive to players who prefer strategic maneuvering to razor-sharp attacks.
• Delayed king safety: Because Black sometimes postpones castling, White must calculate tactics around an exposed black king in the center—especially if h3 forces the bishop back to d7 or e6.

Historical Significance

The line rose to prominence in the early 1950s when Vassily Smyslov used it against Mikhail Botvinnik in their 1954 World-Championship match. Anatoly Karpov later adopted it as a mainstay, employing it in several candidates’ events (e.g., Karpov – Polugaevsky, Moscow 1971) and World Championship encounters. Its reputation is that of a solid yet dynamic alternative to the ultra-theoretical Classical and Mar del Plata variations.

Illustrative Games

• Smyslov – Botvinnik, World Championship 1954 (Game 7)
  Smyslov’s accurate central play demonstrated that White can maintain a small edge by avoiding premature pawn thrusts.
• Karpov – Kasparov, Moscow 1984 (abandoned WCh, Game 9) A classic strategic duel in which Kasparov used 5…Bg4 to divert the game from Karpov’s pet Classical lines. The struggle featured a long maneuvering phase and ended in a hard-fought draw after 62 moves.
• Fischer – Reshevsky, USA Championship 1961 Fischer tried the aggressive 6.h3 Bxf3 7.Qxf3, but Reshevsky equalized comfortably, showing the robustness of the structure for Black.

Typical Plans for Each Side

• White
  • Break the pin with 6.h3 or 6.Be2 while maintaining the strong pawn center.
  • Expand on the queenside with b2-b4 and c4-c5 if Black delays …e5.
  • Target an under-protected d6 pawn after exchanges on f3 weaken Black’s dark squares.
• Black
  • Trade on f3 to damage White’s pawn structure or retreat the bishop to d7/e6, keeping options open.
  • Strike with …c5 or …e5 once the pin reduces White’s central control.
  • Sometimes delay castling and launch a timely …f7-f5 if circumstances favor a kingside initiative.

Common Tactical Motifs

• Forks on e4 & c4: After …Bxf3 …Nxe4, Black’s knight may hop into c3 or d2 creating double attacks.
• Exchange sacrifice on f3: In sharp lines, Black can sacrifice an exchange on f3 (…Rxf3) to open the g-file versus the white king.
• Central breaks: If White castles kingside too early, …e5 dxe5 dxe5 can reveal tactics against the queen on d1 or bishop on g2 after a later …Qxd1+.

Interesting Facts & Anecdotes

• When Kasparov was asked in an interview why he seldom played 5…Bg4, he quipped, “Too quiet for my taste—my bishops prefer attacking diagonals, not pinning ones.”
• In correspondence chess, the move 6.Qb3 has scored exceptionally well, prompting a resurgence of interest in engine-assisted analysis of the line.
• The system inspired a Russian saying among junior coaches: “Pin the knight, freeze the center,” emphasizing how the simple pin can stall White’s ambitious pawn storms.

Modern Status

Although not as fashionable as the main Classical KID today, the 5…Bg4 line remains a reliable surprise weapon, especially in rapid and blitz games where forcing an opponent into less-trodden territory carries extra value. Several grandmasters—among them Dmitry Andreikin and Pentala Harikrishna—have reintroduced it into top-level practice after finding novel engine-backed improvements.