Kan Variation, Wing Attack

The Wing Attack extends the Kan's pawn play at once. Instead of the flexible 5...Qc7, Black advances 5...b5 to threaten ...b4, which dislodges the c3-knight and weakens White's grip on e4, while ...Bb7 adds pressure along the long diagonal. The cost is development: Black's kingside pieces stay at home a little longer, and the advanced b-pawn can become a target. The most common reply is 6. a3, which rules out ...b4. Other choices are 6. Be3 and the engine's preferred 6. Bd3, which covers e4 directly. A g3 fianchetto is a further option, usually reached by a different move order and named the Fianchetto Variation.

After 6. Bd3 Qb6, Black's queen hits the d4-knight. Two named lines follow. In the Spraggett Attack, 7. Nf3 retreats the knight from the pressure. In Christiansen's Dream, 7. Be3 Bc5 8. Qg4 meets Black's play against d4 with a strike at g7. The engine considers the position roughly balanced. In online play Black scores well, winning slightly more than half the games.