Strategy
Good and Bad Bishops
A bishop stays on one colour for the whole game. A light-squared bishop will never touch a dark square, and that simple fact explains a great deal of chess strategy. Your pawns are the pieces that move least and change least, so the colour of the squares they stand on decides whether your bishop has room to work or spends the game staring at its own army.
What makes a bishop good or bad
The working definition is short: a bishop is bad when most of your central pawns stand on its colour, and good when they stand on the other colour. The pawns that matter most are the fixed ones in the center, the pawns that are blocked by enemy pawns and cannot easily move again.
If your pawns sit on dark squares, they block the diagonals of your dark-squared bishop. That bishop cannot attack the enemy's pawns that face yours, because those enemy pawns are on light squares. Meanwhile the light squares around your pawns, the ones your pawns no longer control, need guarding, and your dark-squared bishop cannot guard them. A bad bishop is weak twice over: it has poor mobility and it does not cover the holes your pawn structure leaves behind.
In the diagram, every white pawn is on a dark square and every black pawn on a light square. Black's bishop can aim at the white pawns on c3 and g3 and at the squares in front of them. White's bishop can only touch dark squares that Black's pawns do not care about, and it can never attack a single black pawn. Black can also bring the king to light squares such as f5 and e4, where White's bishop can never chase it.
The classic example: the French Defense
The best-known bad bishop in opening theory is Black's light-squared bishop in the French Defense. After 1.e4 e6 2.d4 d5 3.e5, Black's pawns on e6 and d5 are on light squares and the bishop on c8 is hemmed in behind them.
Play through the French Advance and look at the c8 bishop →French players have several standard answers to this problem. One is to break the chain with ...c5 and ...f6 so that the bishop's diagonals open later. Another is to get the bishop outside the pawn chain before playing ...e6, which is one reason the Caro-Kann (1.e4 c6 2.d4 d5) is popular: Black can develop the bishop to f5 or g4 first and only then play ...e6. A third plan is to trade the bad bishop, for example by playing ...b6 and ...Ba6 to offer an exchange of light-squared bishops. The general rule follows from this: trade your bad bishop, keep your good one, and try to leave your opponent with the bad one.
The "tall pawn"
Coaches sometimes call a very bad bishop a "tall pawn". The image is accurate. Picture a bishop on e2 behind its own pawns on d3, e4 and f5, with every diagonal blocked. It moves along a few squares, defends a pawn or two, and otherwise does what a pawn would do. You have the material of a piece but the activity of a pawn.
Two points stop this from being the whole story. First, a bad bishop can still be useful as a defender. Because it is on the same colour as your pawns, it can protect them, and a pawn chain guarded by its own bishop can be very hard to break. Second, "bad" describes the bishop's scope, not its value on the scoreboard. A bad bishop placed outside its pawn chain, for example a French bishop that reaches g6 or h5, can be perfectly active even though the pawns behind it are still on its colour. Before you judge a bishop, ask where it actually is and what it can reach in the next few moves.
How the pawn rule shapes your play
The rule has a practical consequence for every pawn move you make. If you have one bishop left, think about which colour you want your pawns on before you advance them.
- With one bishop, place your fixed pawns on the opposite colour. The bishop then controls the squares the pawns do not, and together they cover the board.
- Against an enemy bishop, put your pawns on the colour that bishop cannot reach when they might become targets. A pawn on a square the enemy bishop can never attack is safe from it forever.
- When you can fix enemy pawns on the colour of their own bishop, do it. You make their bishop bad and their pawns permanent targets for your pieces.
In endgames this matters even more. With only kings, pawns and a bishop each, a good bishop against a bad bishop is often enough to win, because the bad bishop cannot defend the squares its king needs and the good bishop picks off pawns or creates zugzwang.
Opposite-coloured bishops
When one side has a light-squared bishop and the other a dark-squared bishop, the bishops can never attack each other and can never contest the same squares. This produces two very different effects depending on the stage of the game.
In a pure endgame with only kings, pawns and opposite-coloured bishops, the defender has strong drawing chances, often even a pawn or two down. The defending side sets up a blockade on squares of its bishop's colour: a pawn that must cross those squares cannot advance, because the attacker's bishop can never challenge the blockade.
Here White's light-squared bishop can do nothing about the dark square e5. If White pushes e5+, Black can give up the bishop for both pawns with ...Bxe5, fxe5 Kxe5, and a king and bishop alone cannot force checkmate. If White keeps the pawns back, Black simply holds the blockade. Converting an extra pawn in such endings is often impossible.
In the middlegame the effect reverses. With queens and rooks still on the board, opposite-coloured bishops favour the attacker. If you attack on the light squares with your light-squared bishop, your opponent's dark-squared bishop cannot defend those squares at all. In effect you are attacking with an extra piece. So a useful rule of thumb: opposite-coloured bishops are drawish in endings and dangerous in middlegames.
Bishop versus knight
The pawn structure also decides most bishop-against-knight battles. Material tables treat them as roughly equal, both about three pawns, but the position chooses the winner.
| The bishop is usually better when | The knight is usually better when |
|---|---|
| The position is open, with long diagonals | The position is closed and pawns block the diagonals |
| There are pawns on both wings | All the pawns are on one side of the board |
| Play is fast and the bishop can switch wings in one move | The knight has a secure outpost that no enemy pawn can attack |
| The enemy pawns are fixed on the bishop's colour | The enemy bishop is bad, hemmed in by its own pawns |
A knight needs several moves to cross the board; a bishop needs one. That is why a bishop shines with pawns on both wings: it can defend on one side and attack on the other. A knight, though, can reach squares of both colours, which makes it the ideal piece against a bad bishop. A knight anchored on a central outpost, protected by a pawn, with the enemy bishop locked behind its own pawns, is one of the strongest small advantages in chess.
A related idea is the bishop pair. Two bishops together cover both colours, so the main weakness of a single bishop disappears. In open positions the bishop pair is a real long-term advantage, and strong players often give up a little time or structure to keep it. For more on how pieces are valued, see chess piece values, and for the structures that make bishops good or bad, see pawn structure.
How to practise this
- Before each pawn move in a game, ask: does this put a fixed pawn on my bishop's colour? If yes, have a reason.
- When you have a bad bishop, look for three fixes: trade it, bring it outside the pawn chain, or break the pawn chain to open its lines.
- In endgames with opposite-coloured bishops, check whether you can build a blockade on your bishop's colour before you resign yourself to a loss.
- Set up a position with a good knight against a bad bishop on the analysis board and play it out against the computer from both sides.