Katalimov Variation

With 2...b6 Black prepares ...Bb7, aiming the bishop at e4 and down the long diagonal instead of committing the d- or e-pawn first. The idea is flexible, but it does nothing to stop White from opening the center. The usual and strongest reply is 3. d4, which accounts for the largest share of games and leads to 3...cxd4 4. Nxd4 Bb7, an Open Sicilian in which Black's development lags slightly. Less frequent tries are 3. Bc4, pointing at f7, and 3. Nc3.

The main structural cost of the fianchetto is weakness on the light squares, particularly c6, d7 and the a4-e8 diagonal. A well-timed Bb5 or Nb5 can exploit these, and the danger grows once Black plays ...d6. After 5. Nc3 Nc6 6. Be3 Nxd4 7. Bxd4, for instance, the natural 7...d6 is a blunder that loses the queen to 8. Bb5+. The line is uncommon. White scores well in practice, and the engine gives White a slight edge.