The Fork
A fork is one piece attacking two things at once. Your opponent can only answer one of them, so the other one is yours - and the knight is the piece that does it most, because it attacks from squares nothing can attack back from.
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A fork is one move that attacks two things at once. Your opponent gets a single move to answer it, so one of the two is going to fall.
Everything else about tactics follows from that arithmetic: one move cannot answer two threats. The whole game is played on it.
Here is the fork that costs beginners the most material, and it is worth finding rather than being shown.
The black king is on e8 and a rook on a8. Your knight on d5 has eight squares. Tap the one that attacks both of them.
That double attack with check is called a family fork when the queen is on the board too - king, queen and a rook, all at once, and the check means the defender has to deal with the king first.
Why the knight is the forking piece
Every piece can fork. The knight is simply best at it, and the reason is geometry rather than strength.
A rook forking two pieces stands on a rank or a file - lines those same pieces often stand on, and can therefore defend along or block. A knight stands somewhere else entirely. A queen can never attack a knight that is attacking her, unless something else does the work.
That is also why the two pieces most often lost to a fork are the queen and the rook: they are the pieces worth taking, and they are exactly the pieces that cannot answer a knight.
The cheapest fork there is
A pawn attacks two squares. It costs one point. Put it where those two squares have pieces on them and the arithmetic is brutal.
A knight on c6, a bishop on e6, and your pawn on d4. One push attacks both.
The pawn fork works because of value, not geometry: the defender usually cannot take the pawn, and would not want to even if they could.
The forks worth watching for
| forking piece | what to look at |
|---|---|
| knight | c7 / f7 / c2 / f2 - one knight there hits the king, a rook corner and often the queen |
| pawn | any push that lands beside two minor pieces standing on the same rank |
| queen | two loose pieces on any two of her eight lines - she forks more often than any other piece, and gets forked more often too |
| rook | two pieces on one rank or file, most often on the seventh, where the king and the pawns both live |
| king | in the endgame, a king next to two loose pawns is a fork like any other |
The defence is always the same and it always happens early: keep your pieces off the shapes that a knight can hit from, and look at every knight that is two moves away from a square like c7. Once the fork arrives with check, there is nothing left to work out.
Once you can see forks, the other two tactics on the same shelf are easy - the pin and the skewer both attack two pieces too, just along one line instead of two.
Try it
Same position as the board above - now play the fork.
Common questions
- What is a fork in chess?
- A single move that attacks two or more enemy pieces at the same time. The defender gets one move to answer, so at most one of the attacked pieces can be saved - the rest of the material is simply won. Fork and double attack mean the same thing; "fork" is used most often when the attacker is a knight or a pawn.
- Why are knight forks so dangerous?
- Because of the shape of the knight's move. A rook attacking two pieces stands on a line those pieces can often defend or block; a knight attacks from a square that no queen, rook, bishop or pawn on those squares can attack back. The defender frequently cannot capture the forking knight at all, which is why the knight fork is the tactic beginners lose the most material to.
- What is a family fork?
- A knight check that hits the king, the queen and usually a rook at the same time - most often landing on c7 or f7, where a knight attacks both back-rank corners and the king's starting square. Because it is check, the defender has to answer the check first, and the queen goes.
- Can a pawn fork?
- Yes, and a pawn fork is the cheapest of all. A pawn attacks two squares diagonally, so a single push can hit two pieces at once - and since the pawn is worth one point, the defender can rarely afford to take it even when taking is possible. Pushing a pawn to attack two minor pieces is one of the most common ways material changes hands.
- How do I stop a fork?
- Before it happens, not after. Watch the squares a knight could reach in two moves, keep your king and queen off the same colour and off knight-move geometry from each other, and be suspicious whenever a knight is three squares from both. Once the fork lands with check, there is usually nothing left to do.
- Is a fork the same as a double attack?
- In practice yes. Some writers reserve "double attack" for two separate threats created by one move - a piece attacking one thing while uncovering an attack from behind it - and use "fork" only for one piece hitting two. The tactic you win material with is the same either way.
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