Pawn Structure 101: Boleslavsky's Hole Part I

The above position is a well-known pawn structure resulting from the Sicilian Defense, namely, the Najdorf, Kalashnikov, and Sveshnikov variations although it can arise from a few others. Note the hole on d5, which is the outstanding feature of this structure, and black's backward d6 pawn. 

In this structure are very specific ideas and goals for each player. For white, an f2-f4 break is one objective while using the d5 square as an outpost is another; many times you will see these ideas combined. Black, on the other hand, has the idea of a minority attack on the queenside and would desperately like to be able to play d6-d5 to equalize the position. For both sides, play will predominantly revolve around the d5 square with white trying to attack and occupy it and black defending and looking for a way to push the pawn. White will also look for ways to exploit the d6 pawn, sometimes castling queenside and piling his major pieces on the d-file. Often when white goes queenside, the black king will remain in the center, at least for a while, where it is actually quite safe in many cases.

As far as piece play goes, white - as said before - would love to get a knight to d5. If achieved, white would have a commanding positional advantage. Therefore, black's c8 bishop ends up on either e6 or b7 following an a6 and b7-b5 push, in both cases eyeing the d5 square. Black normally has a knight on f6 as well, which is a critical defender of d5 - this is why white usually plays Bc1-g5 at some point an exchanges the dark square bishop for the f6 knight in an attempt to undermine d5 (one reason black's b8 knight goes to d7 so as to recapture on f6 with another knight to maintain the defense of d5). Given that this is an open, or semi-open, position, it's a bit odd that in this particular structure knights tend to fare better than bishops; this is because of the importance of d5.

First, let's take a look at a game where white prevails in his goal of winning the d5 square and, eventually, the game as well. This game was played in the 2016 Olympiad at Baku: