FEN notation

Have you ever wanted to send someone an exact chess position without having to explain move by move how it was reached? That’s what FEN notation is for.

It’s a single line of text that describes the complete state of the board at a given moment. Copy it, paste it into any viewer or engine, and you’ll see the position instantly.

What FEN means

FEN comes from Forsyth-Edwards Notation. Unlike PGN — which narrates the whole story of a game — FEN only captures the current snapshot. Where the pieces are, whose turn it is to move, what rights remain. Nothing more, nothing less.

The six fields of a FEN

Let’s dissect the string. A FEN always has six parts separated by spaces:

1. Piece placement — what’s on each square
2. Active color — who moves now
3. Castling rights — which castling options are still available
4. En passant target square — if that option exists
5. Halfmove clock — moves since the last pawn move or capture
6. Fullmove number — which move number the game is on

How to read the first field

The first block is the densest. It goes through the board from the eighth rank to the first, file by file. White pieces are uppercase and black pieces are lowercase:

• K Q R B N P for White (king, queen, rook, bishop, knight, pawn)
• k q r b n p for Black

Numbers indicate consecutive empty squares. If you see an 8, that whole rank is empty.

Example: the starting position

Let’s take the easiest case. The starting position of chess is written like this:

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

What does each part tell us?

• All pieces are in their starting spots
• White moves (w)
• Both sides keep both castling rights (KQkq)
• No en passant capture is available (-)
• No pawn has moved and there have been no captures (0)
• We’re on move 1

Once you get the hang of it, reading a FEN takes seconds.

Try it yourself with the viewer

Below you have the PGN viewer loaded with that starting FEN. Swap it for any position you’re interested in and instantly check whether the string describes what you wanted. It’s the fastest way to understand how it works.

That makes FEN an essential tool: for studying endgames, saving specific exercises, or sharing a position in one click.

FEN vs. PGN: when to use each

• FEN: tells you where we are now.
• PGN: tells you how we got here.

The two formats complement each other. If you want to analyze a standalone position, use FEN. If you want to review a complete game with algebraic notation, use PGN. Learn both and you’ll have the complete vocabulary.