Weaknesses

Introduction

It is impossible to play chess at a high level without the ability to subconsciously avoid blundering pieces. Thankfully, this skill is not too difficult to obtain: play a lot of chess, analyze your games, do a lot of puzzles. Equally necessary but much harder to achieve is the subconscious ability to avoid and exploit weaknesses. For several reasons this ability is much more difficult to develop:

1. Puzzles only focus on weaknesses tangentially
2. Weaknesses will often go unnoticed by both players during a game
3. Unless you are already aware of the concept, it is likely that even decisively weakening moves will be glossed over in game review

How Weaknesses are Made

For the purposes of this article I will define a weakness as follows:

A square that is statically difficult to control better than your opponent

As weaknesses must be at least somewhat static they can be formed in two ways:

1 Pawn Moves
2 Captures

Making either of these types of moves without due consideration is always risky as a result

Pawn Moves

Every time you move a pawn it gives up it's ability to control between 2-4 squares, moving a pawn as well as it's two square adjacent neighbor will create 2-4 squares that can no longer be controlled by a pawn at all (also known as an outpost).

Captures

Pawns being captured or making a capture will create weaknesses through the same mechanism as pawn moves, piece captures are a little bit more complicated.

Losing a Bishop: This weakens either all the light squares or all the dark squares in your position
Losing a Knight: This weakens the squares that the knight would have been able to comfortably control (a knight on f6 can easily control e4 and e5, but will take a long time to control d4)
Losing a Rook: This weakens all ranks and files in the position (so to leverage being an exchange up requires exploiting weak ranks and files)
Losing a Queen: This weakens all squares in your position that your opponent can attack once but not twice as well as all squares that they would like to occupy with their king

What makes a square weak is based on the delta between your ability and your opponent's ability to control a square. As weakening decisions stack up together (such as trading off your dark squared bishop in the Maroczy Bind position above) the more critical a weakness becomes.

The All Important Concepts of Accessibility and Exploitability

Accessibility

If the opposing player cannot access a square, it does not matter if it looks weak optically. Some examples of inaccessibility are included below:

It is important to avoid the trap of playing to create weaknesses in your opponent's camp without a plan for how you intend to access them

Exploitability

Controlling a weak square isn't intrinsically valuable, it must be an instrument to some other end. For example:

1 If a pawn or a piece is on a weak square and either cannot or would not like to move away then winning the square will either win material or force a concession
2 If occupying the weakness allows you to attack other exploitable weaknesses
3 If occupying the weakness restricts your opponent's piece movement
4 If controlling the square allows you to threaten a checkmating attack

Some examples of difficult to exploit weaknesses are included below:

Three Practical Exercises

Answers

1 Black is better, d6 is a backwards pawn but it can be very conveniently defended by black's pieces while the light squared bishop makes it difficult for white to double on the d-file thanks the the weakness of the c4 and d3 squares. Black's h4 pawn could be weak in some positions but here it is impossible to attack. White's problems are much more dire, black's king can easily exploit the weakness of white's dark squares especially f4 to pressure the kingside pawn complex. Additionally, black has the idea b4 on tap which is difficult for white to meet without allowing black to create an isolated and weak b or c pawn

2 Bxc6 and a5 permanently fixes black's weak pawn on b7 while not allowing the tactic Nxa5!, black has little counterplay against white's plan of tripling on the b-file

3 Bxc6 and Na4 creates and exploits an outpost on c5 that will be used to restrict black's light squared bishop and pressure the pawn on c6. White's main positional trumps are black's weak pawn on e6 and weak dark squares