ECO code: A00
Anderssen's Opening with the moves 1. a3 e5 2. g3 d5 3. Bg2 Nf6 4. d3 Nc6 5. Nd2 is an offbeat and flexible opening choice for White. The initial move 1. a3 is somewhat waiting and non-committal, aiming to avoid mainstream theory and provoke Black to claim the center early.
Characteristic: The opening is characterized by a slow buildup with fianchettoed kingside bishop and a solid pawn structure aimed at controlling key squares quietly rather than immediate confrontation. The move 5. Nd2 supports central and kingside development harmoniously.
Attacking or Defensive: For White, this setup is more positional and somewhat defensive in nature, focusing on solid development and control rather than direct attacks. Black’s early central pawns on e5 and d5 are aggressive, aiming to claim space and challenge White’s setup. White will often look to counterattack once development is complete.
Center Control: This opening does not immediately contest the center with pawns but relies on piece pressure and flexible pawn moves like d3 to maintain a foothold. Black, meanwhile, takes a more direct approach to the center with pawns on e5 and d5.
This opening is defined by the position shown on the board below. The moves displayed are a typical sequence that leads to it, but different sequences can reach the same position and still carry the same opening name.