FIDE Laws of Chess
3: The moves of the pieces
It is not permitted to move a piece to a square occupied by a piece of
the same colour. If a piece moves to a square occupied by an opponent's
piece the latter is captured and removed from the chessboard as part of
the same move. A piece is said to attack an opponent's piece if the piece
could make a capture on that square according to Articles 3.2 to 3.8.
The bishop may move to any square along a diagonal on which it stands.
The rook may move to any square along the file or the rank on which it
The queen may move to any square along the file, the rank or a diagonal
on which it stands.
When making these moves the bishop, rook or queen may not move over any
The knight may move to one of the squares nearest to that on which it stands
but not on the same rank, file or diagonal.
The pawn may move forward to the unoccupied square immediately in front
of it on the same file, or
On its first move the pawn may move as in (a); alternatively it may advance
two squares along the same file provided both squares are unoccupied, or
the pawn may move to a square occupied by an opponent's piece, which is
diagonally in front of it on an adjacent file, capturing that piece.
A pawn attacking a square crossed by an opponent's pawn which has advanced
two squares in one move from its original square may capture this opponent's
pawn as though the latter had been moved only one square. This capture
may only be made on the move following this advance and is called an 'en
When a pawn reaches the rank furthest from its starting position it must
be exchanged as part of the same move for a queen, rook, bishop or knight
of the same colour. The player's choice is not restricted to pieces that
have been captured previously. This exchange of a pawn for another piece
is called 'promotion' and the effect of the new piece is immediate.
No piece can be moved that will expose its own king to check or leave its
own king in check.
There are two different ways of moving the king, by:
moving to any adjoining square not attacked by one or more of the opponent's
pieces. The opponent's pieces are considered to attack a square, even if
such pieces cannot themselves move
'castling'. This is a move of the king and either rook of the same colour
on the same rank, counting as a single move of the king and executed as
follows: the king is transferred from its original square two squares towards
the rook, then that rook is transferred to the square the king has just
Castling is illegal:
if the king has already moved, or
with a rook that has already moved
Castling is prevented temporarily
if the square on which the king stands, or the square which it must cross,
or the square which it is to occupy, is attacked by one or more of the
if there is any piece between the king and the rook with which castling
is to be effected.
The king is said to be 'in check', if it is attacked by one or more of
the opponent's pieces, even if such pieces cannot themselves move.
a check is not obligatory.