The Positional Rxe6 Sacrifice
Today we are going to talk about a relatively common positional exchange sacrifice - Rxe6 (or Rxe3 for Black). As a rule, a player achieves two main goals with such a sacrifice: 1) eliminates the opponent's Bishop and therefore completely dominates on the light squares (or dark squares for Black). 2) makes the position of the opponent's King more vulnerable.
Even though this concept is pretty simple, it was virtually unknown even for the World's best players before WWII. In cases where they sacrificed an exchange positionally, the resulting attack was so strong that the outcome of the game was never in question. Look at the next famous example. Even though technically the Rxe6 sacrifice was positional, in reality White attack was so strong and irresistible that I cannot even call the Rxe6 move a sacrifice!
Enter Tigran Petrosian and Ulf Andersson. These two great chessplayers are well known for their positional exchange sacrifices. I will never forget the story which was told by an older master who played against the great Petrosian. It was the King's Indian Defense and at some point a part of the position looked like this ( the material was even, but I don't recall the exact position):