Lesson 3: Prophylactic Thinking

Take a look at the following diagram, what should white do here?

Diagram 1

Before we reveal the correct move here for white, lets understand what is Prophylactic Thinking.

Prophylactic Thinking: In chess, prophylaxis consists of a move or series of moves done by a player to prevent their opponent from taking some action. Such preventative moves, or prophylactic moves, aim not only to improve one's position but also to restrict the opponent in improving their own.

Basics of Prophylactic Thinking: 

1. Understand your opponent’s idea. Ask the golden question: What does my opponent wants to do?

1. Try to prevent them. 

Prophylactic thinking is NOT defense! Take a look at the examples from below:

Diagram 2-1(Defense)

Diagram 2-2(Prophylactic Thinking)

In diagram 2-1 it’s black to move. Black plays Nc5 here, when white plays Bc4, defending the the pawn. This is called defense. However, if we compare this to Diagram 2-2, where it is white to move. White uses Prophylactic Thinking to play 1.d4! stopping blacks threat of Nc5. In short, when you are defending, you are trying to stop a ongoing attack. On contrast, prophylactic thinking stops your opponent’s attack before it even happens.

Diagram 3

Black needs to improve his king, but Kg6 is met by g4! By playing 1... Rh8 black is ready to meet g4 by taking the pawn and penetrating with the rook. 

Now, lets head back to our first diagram:

After black’s 10th move: 0-0

For black to improve his position he must try to develop his knight and bishop on the queenside. However, to develop his knight on d7, he must do something about the pawn on e5. One option for black is to play exd4, but this move helps white open the position. Another option would be to play 1... e4, however, this would hang a pawn to Bxe4. Therefore, black must play 1... Bc7 to play e4.  

For white, 11. Ba2 would prevent this, as Bc7 is met by Nb5! 

The full game: