1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.Qc2 d5 5.cxd5 exd5 opens the Nimzo-Indian Defense: Classical Variation, Noa Variation (5.cxd5 5...exd5), ECO E35. With 102,973 games on record, the patterns below come from the largest practical sample available.
History and Notable Players
It arises from the Nimzo-Indian Defense: Normal Variation, Ragozin Variation. Among the most prolific White practitioners are Aleksey Dreev (18 games), Anatoly Karpov (12 games), Viktor Erdos (11 games). Black-side regulars include Andrei Sokolov (13 games), Mikhail Botvinnik (11 games), Alexandra Kosteniuk (10 games).
Performance Across Rating Levels
The picture changes a lot as you climb the rating ladder. At 1200 Elo, the opening shows up in 0.00% of games (2,312 samples). White scores 49.2%, Black 46.6%, draws 4.2%. Move up to 1800 Elo and the share shifts to 0.00%, with White winning 52% versus Black's 42.9%. At the top end (2500+ Elo), popularity is 0.04% with 9.7% draws — a clear sign of how much theory rules the line at master level. Positions also become less sharp as level rises (sharpness 0.96 → 0.90).
Move Diversity and Theory Depth
Move choice is far from uniform in the Nimzo-Indian Defense: Classical Variation, Noa Variation (5.cxd5 5...exd5). At 1200 Elo, the top reply is Bg5, played 25.8% of the time. There are 5 other moves seeing meaningful share, and 66.1% of games stick to established theory. Entropy: 2.70. By 2500, Bg5 dominates at 81.1% of replies; only 3 viable alternatives remain and 94.9% of moves are theory. Entropy drops to 1.07. That entropy collapse is the signature of a line where preparation pays off: at the top, players know the best move and play it.
Common Mistakes
- Drifting away from main theory — At 400 Elo, theory adherence sits at 71.1% — versus 89.6% at 2000. The most popular deviation is Bd2 (played 24% of the time at 400, much less so up top). It looks fine but quietly hands the better-prepared side an edge.
- Neglecting development — It can feel productive to make extra pawn moves early, but falling behind in piece development is what loses most amateur games — especially in open positions where active pieces find squares fast.
- Letting White own the centre — Hypermodern openings concede central space on purpose, but only if you strike back in time. Delay the counter-blow and you end up squeezed.
Practice on Chessiverse
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