Note: This system will try to fill in empty opening information.
ECO Code for opening (form XDD or XDD/DD):
Text name of opening (e.g. 'Ruy Lopez'):
Text name of opening variation:
A FEN records in one line of text the following information:
the piece placement, the color to move next (b or w), the castling availability,
the en passant target square, the halfmove clock, and the fullmove number.
Each of these pieces of information is separated by a space character.
Piece placement is given in left-to-right, top-to-bottom order
(from White's perspective).
White pieces are identified by uppercase SAN piece letters ("PNBRQK") and black
pieces are identified by lowercase SAN piece letters ("pnbrqk"). Empty squares
are represented by the digits one through eight; the digit used represents the
count of contiguous empty squares along a rank. A solidus character "/" is
used to separate data of adjacent ranks.
The third field represents castling availability. This indicates potential
future castling that may of may not be possible at the moment due to blocking
pieces or enemy attacks. If there is no castling availability for either side,
the single character symbol "-" is used. Otherwise, a combination of from one
to four characters are present. If White has kingside castling availability,
the uppercase letter "K" appears. If White has queenside castling
availability, the uppercase letter "Q" appears. If Black has kingside castling
availability, the lowercase letter "k" appears. If Black has queenside
castling availability, then the lowercase letter "q" appears.
The fourth field is the en passant target square. If there is no en passant
target square then the single character symbol "-" appears. If there is an en
passant target square then is represented by a lowercase file character
immediately followed by a rank digit. Obviously, the rank digit will be "3"
following a white pawn double advance (Black is the active color) or else be
the digit "6" after a black pawn double advance (White being the active color).
An en passant target square is given if and only if the last move was a pawn
advance of two squares. Therefore, an en passant target square field may have
a square name even if there is no pawn of the opposing side that may
immediately execute the en passant capture.
The fifth field is a nonnegative integer representing the halfmove clock. This
number is the count of halfmoves (or ply) since the last pawn advance or
capturing move. This value is used for the fifty move draw rule.
The sixth and last field is a positive integer that gives the fullmove number.
This will have the value "1" for the first move of a game for both White and
Black. It is incremented by one immediately after each move by Black.
The FEN for the starting position is:
rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
After the move 1. e4 it is:
rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1
Please enter the game moves ("movetext") in the area below.
You can include comments in movetext by surrounding them with
curly braces, e.g. {this is a comment}, or by using a semicolon
(everything in a line after a semicolon is ignored).
The last entry must be a repeat of the result (e.g. "1-0" if white won).
Line breaks and indentation are not significant, but there
must be at least one space or line break between each player's move.
You may indicate move numbers by simply typing the number followed by a
period, and you can use "..." before Black's moves; move numbers are optional.
You must use standard algebraic notation (SAN) as defined in PGN.
Examples of SAN are "Nc3" (Knight to c3),
"e4" (pawn to e4), and "exf4" (pawn on e takes f4).
More formally, a SAN move is
"O-O" (kingside castle), "O-O-O" (queenside castle), or the following pattern:
moving_piece disambiguator x_if_capture destination promotion markings
Where moving_piece is N (Knight), B (Bishop), R (Rook),
Q (Queen), K (King), or nothing if it's a pawn.
Disambiguator is normally empty, but if
more than one piece could move to the destination this identifies the moving
piece; the disambiguator is the file (letter) or rank (number)
the moving piece is moving from (in rare cases both;
if only one is needed use the letter).
The disambiguator must be a letter if the move is a pawn capturing something.
x_if_capture is an "x" if a piece is being captured, else nothing.
The destination is a lowercase letter (a-h) followed by a number (1-8);
when a pawn is capturing the number is optional.
The promotion field is used if a pawn is promoted; when used, it is
an "=" sign followed by the piece the pawn promotes to ("e8=Q" means
pawn moves to e8 and promotes to Queen).
The markings add other information about the move, and are as follows:
check suffix numeric_annotation
The check marking is "+" if that move checks the opponent's king and
"#" if that move checkmates the opponent's king.
The suffix is one of the traditional suffixes:
"!", "?", "!!", "!?", "?!", and "??".
The numeric_annotation is a "$" followed by a numeric code describing the
move, and is usually separated by a space from the main move;
see the PGN standard for more information.
You can describe variations by using parentheses.
These can describe why a certain move wasn't
played, or show should have been played.
An opening parentheses describes a possible alternative sequence
of moves by unplaying the move before the opening parenthesis, "(".
Parentheses can be nested (to show alternatives to alternatives).