Mongredien Defense, with Nc3

The Mongredien Defense with Nc3 arises after 1. e4 g6 2. d4 Bg7 3. Nc3 b6. Black skips the usual 3...d6 of the Standard Defense and prepares ...Bb7, so that both bishops bear on the center from long diagonals. The queen's bishop aims at e4 and the g7-bishop at d4, an extreme version of the hypermodern approach. The plan can grow into Hippopotamus-style setups if ...d6 and ...e6 follow. The drawback is time. With the knight already on c3 covering e4, White can complete development and claim space before Black's pressure has any real effect.

The line sits in the middle of the popularity range among named openings. White scores noticeably better than Black in practice, and engines rate White's position as clearly superior. The most common reply is the natural 4. Nf3. Next comes 4. Be3, which prepares Qd2 and long castling and gives White the best results of the main choices. The more ambitious 4. f4 grabs further space, and Black's practical results against it are closer to level. Engines also suggest 4. Bc4, which develops the bishop toward f7.