
Part of the Advanced Beginner's Chess Guide (Section 2)

Game 3, KW's Major Digression,
7 Patterns You MUST KNOW for
Control of a Square

[Pattern #2]


Knowing When You Control A Square
- PATTERN #2 -

An equal number of pieces is
not the same as Control

  • COA Control is all about counting up the number of pawns or pieces that can move to a square. If you have the same number of pieces, the square is shared. If it is greater, one side has COA Control. This is the basis as well of COA Center Domination. While A GOOD PORTION of the time this would be accurate in assessing Control, it is not ALWAYS accurate. This is a quick and dirty rule of thumb. But as "they" say, the Devil is in the details.

Let's take a couple of examples:

KW's Major Digression, Pattern 2, Diagram 3-6a
Diagram 3-6a
White To Play:
The Attackers and Defenders are Equal.
Would You Hesitate to Attack Here? No!
KW's Major Digression, Pattern 2, Diagram 3-6b
Diagram 3-6b
White To Play:
White cannot move to d5.
Black controls d5.

Dan Heisman (Elements of Positional Evaluation - How the Pieces Get Their Power) uses a similar example as Diagram 3-6a and says:

  • "From this example we can see that if a knight attacks a queen, the queen almost always must move because the trade is unfavorable. However, if a queen attacks an unguarded knight, then guarding the knight is a possibility because then its lower value gives it less absolute vulnerability. It is similar to an army private being more expendable than a general!" (p.49)

So as Heisman points out, Black's Queen (and the square d5) is Vulnerable. Vulnerability is closely tied with Material (COA Point Count).

Since it is White's turn, it does not matter to White whether the Queen is protected or not. White will take the Queen, and win Queen for Knight. If it were Black's turn, Black would have to move his Queen to protect it (the blue squares in Diagram 3-6b show squares Black's Queen could move from Diagram 3-6a without being attacked by a piece next White move).

Moving to e5 would be a nice spot (with check on the White King) but White could play Qe2 and the Queen would be attacked. As well, a5, d6, and d8 would be good spots (as in the Scandanavian Defense). From any of these spots, Black would still guard d5, providing 2 defenders to one attacker.

Even if Black's Queen could not observe d5 (say at f6, where it is in the diagram), Black would still Control d5, as the pawn on c6 prevents White's Knight from landing on d5, as he would lose his Knight without compensation.

Heisman explains Vulnerability this way:

  • "Relative vulnerability is a piece being subject to attack that is dependent on the position of the pieces... Other aspects of vulnerability are weak squares (high vulnerability) and outposts (low vulnerability). One measure of the weakness of a square is the corresponding strength of an enemy piece outposted on the square. The less chance for exchange or threat to evict the enemy occupier, the greater the invulnerability and the greater an asset the outpost piece becomes... One useful guideline taught to beginners is to avoid "hanging pieces," i.e., ones that are not protected, and thus ultimately vulnerable..." (p.49,51,52)

And then:

  • "A piece that is guarded as many times as it is attacked (by pieces of the same value) is barely adequately guarded. You can double-attack a piece that is not guarded at all, and you can just as effectively double-attack a piece that is guarded, but already attacked as many times as it is guarded. So barely adequately guarded pieces are vulnerable. A piece that is inadequately guarded is protected by other piece(s), but not as many times as it is attacked, and is not safe." (p.54)


  • "Any section on vulnerability would not be complete without discussing overprotection, a concept springing from the genius of Aron Nimzovich. Overprotection is protecting a square or piece more than necessary."

  • "A piece, pawn, or even a square that is overprotected may find itself the "invulnerable" cornerstone of a player's position. Not only is vulnerability decreased, but coordination, flexibility, and "plausible" mobility of the army enhanced. For example, flexibility is greatly enhanced by overprotection because when a piece is barely adequately protected, all of the defenders are tied up and usually can't safely move. But if the square the piece is on is overprotected, then any of the defenders can move!"(p.55)

Vulnerability is more important than simply counting up how many pieces are attacking and defending each side. In fact, that is actually one element of Vulnerability. If you will be behind in material in an exchange if you land on a square, you have Vulnerability on that square. You may be exchanging once, twice or more on the square sequentially, but if you are behind at the end, you are Vulnerable, and do not have Control of that square. Alternately, if your opponent lands on a square, and after exchanging you are up in the exchange, your opponent is Vulnerable and you have Control of the square.

Heisman distinguishes between various levels of Vulnerability on p. 53-54. I will not go further into it here.

If both of you can place a pawn or piece on a square and exchange evenly, neither one of you has Control, it is equal. Let's demonstrate this:

KW's Major Digression, Pattern 2, Diagram 3-6c
Diagram 3-6c
Neither Knight can move to c5.
Whoever moves to c5 will lose Knight for Pawn.

That should be sufficient to show the pattern that an equal number of pieces is not the same as Control.

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