Euwe Attack

The Euwe Attack, 2. b3, declines to build the broad center that the main lines of the Caro-Kann Defense allow. Instead, White prepares Bb2 so that the dark-squared bishop bears down the long diagonal toward e5 and the black kingside. The cost is that the e4-pawn receives no immediate support from a d-pawn, so Black's planned ...d5 arrives with gain of tempo against it. The line takes its name from Max Euwe, who used it successfully, including in a 1920 win over Richard Réti. It is seldom played today, and general surveys of the Caro-Kann group it with other second moves regarded as ineffective or doubtful.

Black replies 2...d5 in the great majority of games, striking at e4 at once. Engines also consider 2...e5, which takes the e5-square that the fianchettoed bishop would target. Moves such as 2...d6 and 2...e6 are rare. In the Lichess database the results are almost evenly split between the two sides, and engines judge the position to be roughly balanced.