Arctic Defense

The Arctic Defense answers 1. Nf3 with 1...f6, a pawn move whose aim is to support ...e5 against the knight's pressure on that square. The method is costly. The pawn takes away the f6-square that the g8-knight normally uses, contributes nothing to development, and loosens the e8-h5 diagonal in front of Black's king. The same central goal can be pursued more cleanly with 1...d6, which leaves the kingside intact. The engine gives White a clear advantage, and White scores well in online games.

White's most frequent replies are 2. d4, which takes the center directly, 2. g3, a quieter fianchetto setup, and 2. e4, which builds a broad pawn center before Black can establish ...e5. The one named branch, the Drunken Knight Variation, arises after 2. e4 Nh6 3. d4 Nf7. With f6 occupied, the king's knight takes the long route through h6 to f7, where it covers e5 and g5 but blocks the f-file and stands far from the center. The defense is rare at a serious level and is mostly seen as a surprise in casual or online play.