Konstantinopolsky

The Konstantinopolsky arises after 1. e4 e5 2. Nf3 Nc6 3. g3. White does not put the king's bishop on b5, c4 or elsewhere along the f1-a6 diagonal, and instead prepares Bg2, where it stands on the long diagonal behind the e4-pawn. The idea is questioned because the bishop already has easy routes into play, and g2 is not always a good post for it. If White later prefers another diagonal, the advanced g-pawn leaves g2 and h3 weak. Its practical appeal is that it leaves known theory early, and it has been called a form of anti-preparation.

Black most often replies 3...Nf6, hitting e4, followed in popularity by 3...Bc5. The engine also likes 3...d5 and rates the position roughly balanced. The quieter 3...d6 is less common and scores better for White. Overall, Black wins slightly more often on Lichess. According to The Oxford Companion to Chess, Alexander Konstantinopolsky brought the move into master play against Viacheslav Ragozin at a Moscow team championship in 1956. David Bronstein used it against Levente Lengyel at the 1964 Amsterdam Interzonal and named it in his book 200 Open Games.