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What Is FEN in Chess?

FEN — short for Forsyth–Edwards Notation — is a single line of text that describes any chess position completely. One string tells you where every piece sits, whose turn it is, who can still castle, and more. Because it is just text, you can paste a FEN into almost any chess site or engine and instantly load the exact position.

If you have ever copied a position into Lichess or Chess.com, or scanned a board with an app, you have used FEN — even if you never saw it.

What does a FEN string look like?

Here is the FEN for the standard starting position:

rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1

It looks cryptic, but it is just six fields separated by spaces. Once you know the fields, you can read any FEN.

The six fields of a FEN

1. Piece placement. The board, described rank by rank from the 8th rank (Black’s back row) down to the 1st, with each rank separated by a /. Uppercase letters are White pieces (K Q R B N P), lowercase are Black (k q r b n p), and a number means that many empty squares in a row. So 8 is a completely empty rank, and 4P3 means four empty squares, a white pawn, then three empty squares.
2. Active color. w if White is to move, b if Black.
3. Castling rights. Any of K (White kingside), Q (White queenside), k (Black kingside), q (Black queenside). A dash - means no one can castle.
4. En passant target square. If a pawn just moved two squares, this is the square “behind” it (for example e3). Otherwise -.
5. Halfmove clock. The number of half-moves since the last capture or pawn move — used for the fifty-move draw rule.
6. Fullmove number. Starts at 1 and increases by one after each of Black’s moves.

A worked example

Take the starting position again:

rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1

• Field 1 reads the board top to bottom: Black’s pieces rnbqkbnr, then a full rank of black pawns pppppppp, then four empty ranks (8/8/8/8), then white pawns PPPPPPPP, then White’s pieces RNBQKBNR.
• w — White moves first.
• KQkq — everyone can still castle both sides.
• - — no en passant square.
• 0 1 — zero half-moves so far; it is move 1.

That is the whole position captured in one line. Change a single character and you describe a different position entirely.

Why FEN is useful

• Share a position instantly. Send a friend one line of text instead of a screenshot.
• Analyze anywhere. Paste a FEN into an engine or an online board to study it.
• Save puzzles and endgames. A FEN is a tiny, portable snapshot — no image needed.
• Set up a specific position to practice against a bot from that exact spot.

FEN captures a single position. If you want to record an entire game move by move, that is a different format called PGN (Portable Game Notation) — the format ChessCopilot exports when you scan a paper score sheet.

How to get a FEN from a real board or a photo

Typing a FEN by hand is slow and error-prone. The faster way is to let a scanner read the board for you. With ChessCopilot’s position scanner you point your camera at any chessboard — a real board photographed at an angle, a screenshot, or a printed diagram — and the app rebuilds the position and gives you the FEN, along with the best move and the engine evaluation. You can copy the FEN to use anywhere, all on your phone and offline.

Frequently asked questions

What does FEN stand for? Forsyth–Edwards Notation, named after journalist David Forsyth and Steven Edwards, who extended it for computer use.

Is FEN the same as PGN? No. FEN describes one position; PGN records a whole game (all the moves). They are complementary.

Can I turn a photo into a FEN? Yes — a position scanner like ChessCopilot reads the board from a photo and outputs the FEN automatically.