Kotov Variation

The Kotov Variation arises from the Averbakh System of the Modern Defense, where White has built pawns on c4, d4 and e4. It is filed under ECO A42 and is often reached through the move order 1. d4 g6 2. c4 Bg7 3. Nc3 d6 4. e4 Nc6. Rather than transposing to a King's Indian with ...Nf6, Black puts the queen's knight on c6, where it joins the g7-bishop against d4 and supports a later ...e5. The cost is that the c-pawn is blocked, so the ...c5 break is not available, and the knight can be driven away.

White's most frequent reply is 5. Be3, which reinforces d4. 5. Nf3 is the next most common choice, and 5. d5 gains space with tempo by chasing the knight, closing the center. Engines prefer 5. d5, along with 5. Be3 and 5. Nge2, and give White a slight edge. In online practice, however, Black's results in this position are marginally better than White's, and the line is a moderately common way to avoid mainstream King's Indian theory.