Nimzo-Indian: Three Knights, 4…c5
Nimzo-Indian: Three Knights, 4…c5
Definition
The position reached after 1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Nf3 c5 is called the Nimzo-Indian, Three Knights Variation, 4…c5. • “Nimzo-Indian” identifies Black’s early …Bb4 pin. • “Three Knights” refers to the only developed minor pieces: White’s knights on c3 & f3 and Black’s knight on f6. • The move 4…c5 is Black’s immediate pawn thrust that attacks d4, invites structural transformations, and keeps transpositional options open.
Typical Move-Order
Strategic Themes
- Central tension: …c5 hits d4 before White can stabilise with e3–e4, forcing an early decision about the centre.
- Transpositional crossroads: Depending on White’s 5th move, play may resemble a Modern Benoni, a Semi-Tarrasch, a Catalan, or an IQP game.
- The pin on c3: Black keeps the knight under pressure, discouraging e2–e4 and supporting tactics such as …Bxc3+ followed by …Ne4.
- Piece activity over pawn structure: Black accepts potential IQP or hanging pawns in exchange for rapid development and active squares.
Main Branches after 4…c5
- 5. g3 cxd4 6. Nxd4 O-O 7. Bg2 d5 – Grünfeld-flavoured positions.
- 5. d5 b5!? – Keres’ Benoni idea, grabbing space on the queenside.
- 5. e3 cxd4 6. exd4 d5 – Semi-Tarrasch structure; quiet but strategically rich.
- 5. a3 Bxc3+ 6. bxc3 d6 – White owns the bishop pair, Black relies on dark-square play.
Plans for Each Side
- White
- Build a broad pawn centre (d4–e3–e4 or d4–d5).
- Fianchetto with g3/Bg2 to overprotect d5 and attack on the long diagonal.
- Exploit the bishop pair and target weaknesses on c5, d5, or hanging pawns.
- Black
- Undermine with …d5, …cxd4, and sometimes the sharp …b5 break.
- Maintain the c3 pin to restrict e4 and create tactical pressure.
- Seize dark-square outposts (e4, c5) and use the half-open c-file for counter-play.
Tactical Motifs to Know
- The skewer …Bxc3+ followed by …Ne4 hitting c3, f2, and sometimes g3.
- Exchange sacrifice …Rxf3 when the g- and c-files are weak.
- Benoni-style pawn storm …b5–b4 after 5. d5.
- Queen excursions to a5 or b6 that triple-attack c4, d4, and b2.
Historical Highlights
Popularised by Paul Keres and Efim Geller in the 1950s, 4…c5 became a staple of Anatoly Karpov’s repertoire in the 1970s. Modern grandmasters such as Fabiano Caruana, Ding Liren, and Anish Giri still rely on it, proving its enduring soundness.
Illustrative Game
Anatoly Karpov – Viktor Korchnoi, Candidates Final (Game 2), Moscow 1974
The game demonstrates how Black’s early …c5 yields active piece play and pressure on the IQP; only Karpov’s end-game skill converted the small structural edge.
Interesting Facts
- Engines originally disliked 4…c5 because it vacates d5; modern evaluation shows the move is fully sound and often preferred.
- Karpov both exploited and employed 4…c5, reflecting his pragmatic approach to opening theory.
- Commentator GM Daniel King once dubbed the knights on c3, f3, and f6 “the knight’s tent” during the 2018 Candidates coverage.
- Garry Kasparov used 4…c5 in exhibitions to create unbalanced positions against lower-rated opponents, showing its practical sting.
Further Study
- Opening for Black According to Karpov – A. Khalifman (chapter on 4…c5).
- The Nimzo-Indian Move by Move – Everyman Chess.
- Replay recent games by Caruana, Ding, and Giri for fresh ideas in the 4…c5 systems.