FEN (.fen)

Background

    • Standard notation for describing positions of a chess game.
    • FEN is an acronym for Forsyth–Edwards Notation.
    • A single FEN string describes one state of the chess game.
    • A FEN file often stores a number of positions described with a FEN string.
    • ASCII format.
    • First developed by Scottish journalist David Forsyth; later extended by Steven J. Edwards.
    • FEN strings are used in PGN files to describe the initial position of a game.

Import & Export

  • Import["file.fen"] imports a FEN file, returning graphics showing the positions.
  • Import["file.fen",elements] imports the specified elements.
  • See the following reference pages for full general information:
  • Importimport from a file
    CloudImportimport from a cloud object
    ImportStringimport from a string
    ImportByteArrayimport from a byte array

Import Elements

  • General Import elements:
  • "Elements" list of elements and options available in this file
    "Summary"summary of the file
    "Rules"list of rules for all available elements
  • Game elements:
  • "ActivePlayer"player who moves next
    "FENStrings"FEN string for the move
    "MoveNumber"the move number of the game
    "PositionRendering"a Graphics rendering of the position
  • Import by default uses the "PositionRendering" element for the FEN format.
  • Move numbers should not necessarily correspond to the actual number of the move in the game. Typically, 0 means an unknown move number.
  • Overall file element:
  • "PositionCount"number of positions stored in the file

Options

  • Elements that involve rendering a chessboard take the following options:
  • "BoardOrientation"Automaticon which side of the board to place white pieces
    "Icons"Automatica set of icons to use for chess pieces
    "SquareColors"Automatica list of two colors for light and dark squares

Examples

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Basic Examples  (1)

Render a chessboard from a FEN string:

Scope  (1)

List available Import elements:

Import Elements  (8)

ActivePlayer  (2)

See which player is to move in the given position:

Get the active player in the 4th position in the sample FEN file:

FENStrings  (1)

Get all positions from a FEN file as FEN strings:

Get the last 5 positions:

MoveNumber  (1)

Extract move number from a FEN string:

PositionCount  (1)

Get number of positions listed in a FEN file:

PositionRendering  (2)

Render position described by a FEN string:

Render positions 5 to 8 from a FEN file:

Summary  (1)

Get a summary of a FEN file:

Import Options  (5)

"BoardOrientation"  (3)

Render a position from black's perspective:

Render a position with white pieces on the left side of the board:

By default, Import displays white pieces at the bottom:

"Icons"  (1)

Use a custom set of icons for kings and pawns:

"SquareColors"  (1)

Specify custom colors for chessboard squares:

Properties & Relations  (2)

FEN strings are often used in PGN files to store starting positions:

Import can produce FEN strings for any position that occurred in a game from a PGN file:

Possible Issues  (1)

Even though technically incorrect, FEN strings without move numbers are accepted by Import:

FEN strings without information about player to move, castling rights or en-passant square are not accepted: