Strategic focus on controlling either all light squares or all dark squares, especially if the opponent lacks that bishop.
Why it matters
Every square is light or dark, and a bishop only ever touches one colour. When one side loses a bishop, every square of that colour in their position gets slightly harder to defend, and the effect adds up across the whole board.
This is why trading a fianchettoed bishop is treated as a concession. The squares it guarded do not become weak one at a time; they become weak all at once, and the pawns cannot cover them because pawns near a king are usually on the other colour.
See it on a board
Every black pawn in the centre stands on a light square, and the dark-squared bishop that used to cover the rest is gone. White's bishop works on the colour nothing defends.
Checked: the position really has the feature described.
How to play it
- Notice which coloured squares your pawns stand on: those are the squares your pawns cover and your same-coloured bishop does not need.
- If the opponent has lost a bishop, put your pawns and pieces on the colour it used to guard.
- Aim to trade the pieces that defend that colour, especially the opposite-coloured bishop.
At each level
The same idea, said the way it is taught at each age.
Queen · ages 8–11
When one bishop is gone, count the pawns on each colour. A pawn on the same colour as your remaining bishop is a pawn in your own way.
King · ages 10 and up
The strongest version is the dark-square bind around a castled king with no dark-squared bishop. It is worth a pawn, sometimes more, because no amount of piece defence fully replaces the bishop.
What goes wrong
- Trading the fianchettoed bishop for a knight to win a pawn, and never solving the squares afterwards.
- Placing your own pawns on the colour of your good bishop, which blocks it.
Questions people ask
- Is a colour complex the same as a weak square?
- It is a whole set of them. One weak square can be covered by a piece; a weak colour complex has too many squares for the pieces to cover at once.