411 REFERENCE · Wikibooks
Chess Opening Theory/1. d4/1...Nf6/2. c4/2...e6/3. Nc3/3...Bb4/4. Bg5/4...h6/5. Bh4
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
Nimzo-Indian Defence rd nd bd qd kd rd pd pd pd pd pd pd pd nd pd bd pl pl bl nl pl pl pl pl pl pl rl ql kl bl nl rl
Nimzo-Indian Defence, Leningrad Variation
5. Bh4
The bishop retreats, since taking on f6 would accomplish nothing. Now Black has the idea of playing ...g5, but he shouldn't be too eager to weaken his kingside right away. The threat of breaking the pin is enough to keep White from playing e4 for now, so Black should address the center. 5...c5, forcing White to advance his d pawn, is the most common move, but 5...b6 is also playable, with Black either fianchettoing after 6. e3 or pushing c5 after all following 6. f3.
Nimzo-Indian Defence