Hedgehog, Bishop and Knight..
I would like to talk about a particular situation, which usually happens out of the Hedgehog opening. Black has a6, b6, d6 and e6 pawn structure and white tries to attack the d6 pawn with a bishop maneuver to f4, while his major pieces are already doubled on the d-file. Black can put his knight on e5 to block the bishop’s attack on the d6 square. In this case one should evaluate what would happen if white traded his bishop for the knight. One advantage of such a trade is doubled pawns on the e-file for black. As we will see in the following examples, creating doubled pawns for the opponent does not always give advantage, one has to take into account more factors. These are: piece placement after the exchange, whether it is possible for the opponent to take over the center due to pawns e6, e5, and who would be faster in activating their pawn majorities. We will address some of these issues as we will look through the examples.
At the board a typical Hedgehog position is defined by black pawns lined up on the 6th rank. White has a space advantage but black’s position is very solid because the row of pawns on the 6th rank guard all the important squares. D6 is the main weakness in black’s position and with his last move Ne5 black defended the pawn. Ne5 is very well placed: besides protecting d6 it attacks the weakness on c4. White decides to trade his bishop for the knight. The downsides of this decision are the loss of the black-squared bishop, the loss of control of d4 and f4. There are advantages to it: open d file, pawn majority on the queen side and most importantly black’s two bishops cannot get into the game since the e4 and e5 pawns block them. Black has to play by using the d4 square and pawn majority on the kingside but in the given situation it is hard to achieve because his pieces are not ready for this task.