Nimzo-Indian Defense: Keres Variation

Nimzo-Indian Defense, Keres Variation

Definition

The Nimzo-Indian Defense, Keres Variation is a branch of the Classical (4.Qc2) Nimzo-Indian that begins with the moves:
1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 c5
The fourth-move thrust …c5, popularised by the legendary Estonian grandmaster Paul Keres, challenges White’s centre immediately and creates positions that can resemble the Tarrasch Defence, the Benoni, or IQP (isolated queen’s pawn) structures, depending on White’s reply.

Typical Move Order and Branches

After 4…c5, the three main continuations are:

1. 5. dxc5 – the most theoretical line, grabbing the pawn and forcing Black to prove compensation. A sample continuation is
   5…0-0 6. a3 Bxc5 7. Nf3 b6, when Black regains the pawn with active pieces.
2. 5. e3 – calmly reinforcing d4. Play often transposes to an IQP after 5…cxd4 6. exd4 d5, echoing the Tarrasch Defence.
3. 5. d5 – avoiding exchanges and steering the game into Benoni-type structures. Black can answer 5…exd5 6. cxd5 d6.

Strategic Ideas

• For Black
  • Immediate pressure on d4, preventing White’s intended e2-e4.
  • Flexible pawn structures; Black may accept an IQP, transform into a hanging-pawn duo on c5/d5, or transpose into Benoni themes.
  • The queenside majority (a7-b7-c5) often drives play in endgames.
• For White
  • Maintaining the bishop pair by recapturing on c3 with the queen.
  • Targeting Black’s IQP or hanging pawns with piece pressure.
  • In the 5.dxc5 line, rapid development and central control while Black spends tempi recovering the pawn.

Historical Background

Paul Keres began experimenting with 4…c5 in the late 1930s, seeking a more dynamic antidote to 4.Qc2 than the traditional …d5 setups. Although the line temporarily ceded a central pawn, Keres demonstrated that swift development and pressure on d4 often yielded full compensation. His games against contemporaries such as Flohr (Stockholm 1938) laid the theoretical foundations. Today the variation is catalogued under ECO code E42 and remains a staple in the repertoires of dynamic players.

Modern Usage and Popularity

Elite grandmasters including Magnus Carlsen, Levon Aronian, Alexander Grischuk, and Maxime Vachier-Lagrave have employed the Keres Variation in recent super-tournaments. Its appeal lies in avoiding the heavy theory of 4…d5 while retaining rich, unbalanced middlegames. [[Chart|Rating|Classical|2000-2023]]

Illustrative Games

• Aronian – Carlsen, Tata Steel 2012
  A textbook example of Black’s dynamic compensation in the 5.dxc5 line.
  
  
• Keres – Flohr, Stockholm 1938
  The origin game that gave the variation its name; Keres, playing Black, shows precise timing in regaining the c5-pawn and seizing the initiative.
  
  

Interesting Facts and Anecdotes

• In 2014, Fabiano Caruana prepared the Keres Variation as a surprise weapon for the Candidates Tournament but never got a chance to unleash it because his opponents steered into the Rubinstein (4.e3) instead.
• The line is one of the rare Nimzo set-ups where Black can castle before deciding whether to exchange on c3. This flexibility keeps White guessing.
• Computer engines initially disliked 4…c5, evaluating the pawn sacrifice pessimistically. With depth, however, they now confirm full equality, mirroring Keres’s original over-the-board conclusions.

Further Study Tips

1. Analyse model games where Black accepts an IQP versus games where Black regains a healthy structure; notice the differing endgame plans.
2. Practice the critical 5.dxc5 line from both sides in training games— mastering the delicate timing of …b6 and …Na6 is essential.
3. Compare the resulting middlegames with the Tarrasch Defence to internalise typical piece placements.