Why not 4.e3 Bxc3+ in the Nimzo-Indian?

Question

Why is 4.e3 Bxc3+ almost never played in the Nimzo-Indian, with idea of 5.bxc3 c5, considering that this is a relatively feared move after 4.e3 c5 5.Nf3 Bxc3, et cetera (Huebner Variation), so that a lot of White players switched to 5.Ne2 to avoid this system in recent times?

[fen ""]
[title "Nimzo-Indian Defense with 4. e3 Bxc3+"]
[startply "7"]
[startflipped "1"]

1. d4 Nf6
2. c4 e6
3. Nc3 Bb4
4. e3 Bxc3+
5. bxc3 c5

Same question from a different perspective: is one tempo that important in a relatively closed position? (e.g. 4.a3 Bxc3+ is generally considered a good game for Black). Then why shouldn't it be after 4.e3 Bxc3?

Answer 1

In this case, one tempo is important due to the concrete nature of the current position. White doesn't have to use it to play Nf3:

4.e3 Bxc3 5.bxc3 c5 6.Bd3, and if Black plays in the style of the Huebner with 6...Nc6 then White has 7.Ne2! and now 7...d6 8.0-0 e5 9.Ng3! gives White an edge (Stockfish says around +0.60). His knight controls the key e4- and f5- squares, and an f4 push is coming soon. This position is a major improvement for White over the normal Huebner system, where instead of playing Ne2-Ng3, White plays Nf3-Nd2 (to avoid Black's threat of playing the ...e4 fork). A knight on g3 can become an active attacker on the kingside, while a knight on d2 just blocks in the c1-bishop.

Note that if Black refuses to play in the style of the Huebner (6...Nc6, 7...d6, 8...e5) then White plays an early e4 push and gets a crushing position in the centre.

Answer 2

The variation beginning 4.e3 Bxc3+ is not very popular, but it is better than its reputation, and it's a very efficient way of cutting out a lot of theory if you're just taking up the Nimzo-Indian as Black. It hasn't been tried and found wanting; it just hasn't been tried (very much).

Essentially, Black would like to set up a dark-square pawn structure and would be happy to transpose into the Huebner Variation should White be so inclined. As II has pointed out, White's main way of avoiding the Huebner Variation is to choose Ne2-g3 instead of the more direct Nf3. But Black can generate pressure against White's center with or without ...e5, and in the Ne2-g3 lines he may well adopt the setup 5.bxc3 d6 6.Bd3 c5 7.Ne2 Nc6 (or even ...b6) 8.e4 0-0 9.0-0 b6 when he has ideas like ...Ba6 and ...Na5 or even ...Nh5 and ...Qh4. Stockfish 10 chews on the position for a while and coughs up an evaluation of 0.00. That doesn't mean the position is actually perfectly equal (see the discussion in Sadler and Regan, Game Changer, for some insight on what that 0.00 actually tells us), but it does mean that if you're a human being and you like Black's position and think you understand it, you should feel free to try it out.

At GM level, the Armenian GM Ashot Anastasian (d. 2016) frequently employed 4...Bxc3+, and it shows up occasionally in the practice of GM Paweł Jaracz, GM Leonid Yudasin, GM Dmitry Andreikin, GM Chanda Sandipan, and GM Roman Ovetchkin. In the Mega 2013 database Black scores a respectable 44% with it out of 166 games at master level (2200+ for both players).

Answer 3

It's a Saemisch variation for White, but White has an extra tempo. Perhaps White will be able to build a big center before Black can target the c4-pawn.