True, 6..c6 isn't a main line in the sense that e.g. the Zaitsev Spanish is a main line. But the theory on 4.f3 is still evolving and relatively fresh. The line given by Markovich is generally accepted as the main line of 4.f3 with 8.dc being the most irritating move for Black. This is quite difficult for Black to meet and his winning chances seem to be zero (reasonable drwing chances though if B is prepare to soak up a little pressure!) That's why I asked about 6...c6.

Tripler64 wrote on 04/16/10 at 15:21:52:


It is not difficult for black to meet if prepared, and white has no more winning chances than black in the main lines (that are dead drawn for the most part). Only the lack of winning chances argument stands up.

The only game I've ever lost OTB to 4. f3 (out of 5 games, 4 of which against 2200+ competition, final score being +3 -1 =1) was to IM Taylor when I pressed for more in an equal position. That was also the first time I had ever gotten 4. f3 OTB (the game appears in the chesslive.de database), so my opening play wasn't as good as it should've been.

Many Nimzo players don't bother learning the theory of the opening that deeply (compared to practicioners of the Grunfeld, or Semi-Slav), leading 4. f3 to have tremendous success as a result of the black player being largely unprepared, and white's plans being simple enough that 1600s could probably play the white side.

BPaulsen wrote on 04/16/10 at 18:46:15:


Now there's a claim for you.

BPaulsen wrote on 04/16/10 at 18:46:15:


And there's another.  I'll let those who play OTB sort that out, but it does look like a powerful practical argument for taking up 4.f3.  I myself don't think that White's game is so frightfully easy for an unprepared player to play, however.

In CC I rarely encounter a Black who doesn't know the "right" moves, but I do frequently encounter Blacks who have no idea of the dangers Black faces even in the lines that are nominally adequate for Black.