In this position, Black plays a6 to prepare for b5, aiming to expand on the queenside while also preventing any potential piece incursions from White. The key ideas involve developing the light-squared bishop to b7 after b5, allowing for pressure on the e4 pawn, and potentially launching a counterattack against White's center. This structure often leads to rich play, appealing to players who enjoy dynamic, flexible positions with chances for both sides, while also providing solid pawn structure and development options.
In this position, Black plays a6 to prepare for b5, aiming to expand on the queenside while also preventing any potential piece incursions from White.