Chess Rules

Chess Basics | Chess Rules | Chess Pieces | Playing Online

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The player with White pieces starts first, chooses his/her chess piece and moves it according to rules for this type of the piece (see chess pieces). After each move, the players take turns.

Capturing Opponent's Chess Pieces

None of the chess pieces may move to a square occupied by another chess piece of the same color. However, a piece may move onto a square occupied by an opponent's piece.  When this occurs, the opponent's piece is 'captured' and is permanently removed from the chessboard. The attacking piece is moved to the square of the former captured piece.

Capture in chess If it's White's turn to move,  the following captures are possible in the diagram on the left:
  1. White rook can capture the Black's bishop
  2. White pawn can capture the Black's bishop (pawns move forward, but capture sideways -- 1 square diagonally forward)
  3. White knight can capture the Black's queen

If it's Black's turn to move,  the following captures are possible in the diagram on the left:

  1. Black queen can capture the White's rook
  2. Black queen can capture the White's pawn
  3. Black pawn can capture the White's knight (pawns move forward, but capture sideways -- 1 square diagonally forward)

En-Passant Rule

Before En-passant After En-passant
Before en passant  

After en passant

The Pawn can capture an opponent's pawn 'in passing' or 'en-passant' (since the French expression is commonly used here).
For the en-passant rule to apply, the following two conditions have to be met:
  1. The previous opponent's move had to be made with a pawn that advanced 2 squares from its starting square
  2. The pawn making an en-passant move could have captured an opponent's pawn if it had only advanced just 1 square instead of 2.

In the diagram on the left, en-passant move applies after White pawn moves from a2 to a4. The Black pawn captures the White Pawn on the a3 square.


Pre-castling position. Castling is possible in two directions: left (long castle) and right (short castle)

Before castling


After castling left (long castle):

After castling left


After castling right (short castle):

After castling right

Once in a game each player can make a special 'castling' move. During this 1 move, both the king and one of its rooks are moved. Castling starts by moving the king 2 squares as indicated by arrows. At hessLab, if the castling is legal, the corresponding rook move would occur automatically.

For castling to be legal, the following four conditions have to be met:

  1. all squares between the king and the rook have to be empty
  2. the king cannot be under check
  3. the king and the rook involved could not have moved previously
  4. all squares through which the king is passing during castling cannot be under attack of the enemy pieces.

Promotion Rule

When a White pawn advances to the last 7-th "rank," or horizontal row of squares, or when the Black pawn advances to its last 1-st rank, it is promoted into its owner's choice of a knight, bishop, rook, or queen (it may not become a king). The usual choice for promotion is a queen, the most powerful piece. It is legal for a player to have several queens on the board at the same time. Occasionally, it is better to promote to a knight (to fork two pieces or avoid stalemate--draw) or a bishop or rook (to avoid stalemate-draw). At, when a pawn reaches the eighth rank, a window will pop up asking the pawn's owner to choose which piece to promote to.

Check and Checkmate  

Check and Checkmate example:

Check & checkmate

White king above is under check (attacked by a Black bishop). White king is also checkmated -- no place to turn to and nothing to protect with...

The goal in chess is to capture (or checkmate) the opponent's king. That is why all players have to protect their kings. If an opponent's piece is threatening to capture the king, the king is said to be 'in check'.  It is illegal to move the king onto a square where it would be under attack (in check). If the king is in check, the king's owner must do something to protect the king right away.

To protect the king, the player may try the following three defenses:

  1. move the king to a square where the king is not threatened
  2. block the line of attack (if the attack is not by a knight or a pawn)
  3. capture the opponent's piece that is attacking the king

If none of the the above 3 defenses work, the king is not just 'under check' -- such king is said to be checkmated. With checkmate, the game is over. The side whose king is checkmated


Stalemate & Other Draws



Time Control

The players can elect to use time control to limit the time spent on a game. At, time control can be adjusted via 'Options' button. If there is no checkmate on the board, the player whose time expires first loses, unless there is a draw via stalemate, insufficient mating material, etc.


Rather than wait for a checkmate or a loss due to expiration of time, the player may choose to resign the game. For this purpose, at 'Resign' button can be selected.

Chess Basics | Chess Rules | Chess Pieces | Playing Online