Knight fork patterns

A knight on e5 attacks eight squares: c4, c6, d3, d7, f3, f7, g4 and g6. Two things about that set matter more than the rest of this guide.

First, every square a knight attacks is the opposite colour to the square it stands on. e5 is a dark square; all eight targets are light. So a knight never attacks a piece standing on its own colour, and a knight fork of two pieces is only possible when both pieces stand on the same colour as each other. When you look at an opponent's king and queen, the first question is whether they share a colour. If they do not, no knight fork exists, whatever the knight does. If they do, there may be a square that hits both, and you should find it.

Second, the targets are two files or two ranks apart from the knight and one in the other direction. A knight fork of two pieces therefore needs those pieces to be a very particular distance from each other: on the same rank two files apart (both attacked from the square in between, one rank away), on the same file two ranks apart, or on a diagonal-ish offset of one file and three ranks, or two and two. That sounds like a lot to memorise. It is not: play through a hundred forks and the shapes become one shape.

A fork that hits the king is the strongest version, because the check leaves the opponent no choice: the king moves and the other piece is taken. When the other piece is the queen, players call it a royal fork. When the knight hits king, queen and rook at once, they call it a family fork, and it usually means the game is over.

The squares to know are the ones next to a castled king. Against a king on g8, a knight on e7 or f6 gives check; from e7 it also covers c8, c6, d5, f5 and g6, from f6 it covers d7, e8, h7, g4 and e4. Against an uncastled king on e8, the square is c7: it checks the king and hits a8, e6, d5 and b5 at the same time. Nc7+ winning the rook in the corner is the most played fork in chess, and every beginner has been on the wrong end of it.

The diagram shows a royal fork from the d5 square. White's knight is attacked twice, by the bishop and by the rook, and looks like it has to retreat. Instead it jumps to e7 with check, and c8, where the queen stands, is one of its eight squares. The king steps to h8 and the knight takes the queen. The shape to remember: king on g8, loose piece on c8 or c6, knight reaching e7.

The knight fork you find in a puzzle is already on the board: the square is free, the pieces are in place, you just have to see it. The fork that wins games is the one that is not there yet and can be made. Two questions find it.

Which square would fork? Take the two targets, usually the king and the most valuable loose piece, and find the squares that attack both. There are at most two. Now ask whether your knight can reach one of them in one move, and whether that square is safe. If the square is guarded by a pawn, the fork does not exist; if it is guarded only by the queen and the fork hits the queen, it does, because the queen cannot take and stay out of the fork at once.

Which piece would have to move? If the fork square is reachable but one of the targets is on the wrong colour, or the square is protected, ask what would need to change. Very often it is one thing: a defender that could be captured, or a piece that could be forced onto the right square by a check. That is where a fork stops being a lucky find and becomes a plan.

The two standard ways to build a fork that does not exist yet.

With a check. A check moves the king, and the king lands on a square you choose by giving the check from the right place. If the king's only legal square is a light square two files from a loose light-square piece, a knight check on the next move forks them. The habit: whenever you have a check, look at where the king must go and ask whether a fork square appears.

With a decoy. A deflection or attraction drags a piece onto a fork square by force, usually by offering something on that square. The most famous version is the rook sacrifice on d8 in the diagram. Black's queen defends f7 and stands on the wrong colour to be forked. White plays Rd8+: the rook is loose, but the check has to be answered, and the queen is the only piece that can take. Now the queen stands on d8, a dark square, the same colour as the king on h8, and the knight on e5 reaches f7 with check. King to g8, knight takes queen. White gave a rook and won a queen.

The pattern generalises: sacrifice on the fork square, then fork. When you see a knight two moves from a check on a king, look at every piece a sacrifice could pull onto one of the knight's other squares.

Everything above runs in reverse. The pieces most often forked are the ones that never move: a queen on d8 and a king on e8, a rook on a8 and a king on e8, a rook on f8 and a king on h8. Before you leave your king and a heavy piece on the same colour with an enemy knight three moves away, count the fork squares and make sure each is covered by a pawn. A pawn is the only defender a knight respects, because a knight cannot fork a pawn and anything worth having.

The classic remedy for the c7 fork is to move the rook or to keep a bishop on the c8-h3 diagonal, so that a knight landing on c7 is simply taken. Against an outpost knight in front of your king, the remedy is to challenge it with a knight of your own or to keep it out with a pawn; there is no cheap way to defend all eight squares.

And when a fork is unavoidable, remember that the value of the two forked pieces is what the opponent gets. Moving the more valuable piece out of the fork with a check or a counter-threat is often possible and turns a lost queen into a lost pawn.

Knight forks are unusual in that the pattern is finite. There are only so many shapes, and the ones that decide games at club level are a dozen at most: c7 and f7 against an uncastled king, e7 and f6 against a castled king, the two-apart shapes on a rank and a file, and the decoy into any of them. Drill those until the fork square lights up before you have consciously looked for it.

That is what the fork journey does: a lesson on the geometry, a drill at your rating where the fork is the whole puzzle, and then a test where forks are mixed with other tactics and you have to find them cold. When you are through it, the fork page has puzzles you can play without an account, and the gym serves forks at your level among everything else, which is the only way to know whether you can still see them when nobody says the word.