What are the rules of chess in a nutshell?

Question

I believe the question How to start learning chess? is actually two questions only one of which is a duplicate. This question is a fixed up version of it which asks only the other one of those questions.

Would it be possible to explain the rules of chess in a nutshell? A clear short description of the rules is nowhere to be found but I'm sure it can be explained very simply.

Answer 1

The definitive guide to chess is given in the FIDE Laws of Chess. The game itself is defined by the first five articles and this is short.

There are many more articles, appendices and even guidelines in the FIDE Laws of Chess which cover over-the-board competition rules and practices but these are not required for a basic understanding of the game, only for tournaments.

Answer 2

How to win: preventing the opponent's king from moving while attacking it. This is a checkmate.

That's the goal of the game. The rest of the rules just relate to how each piece moves.

King: Can move one square in any direction.

Queen: Can move any number of squares in any direction, but can't jump over pieces in the way.

Bishop: Can move any number of squares along any diagonal it's on, but can't jump over pieces in the way.

Rook: Can move any number of squares horizontally or vertically, but can't jump over pieces in the way.

Knight: Can move in an L-shape. 2 squares horizontally and one square vertically, or 2 squares vertically and one square horizontally. It can jump over any pieces in the way.

Pawn: Can move one square forward, and has the additional option of moving 2 squares forward if it's on its starting square. However, it captures enemy pieces by moving one square diagonally in either direction. The pawn is unique in that it captures and moves differently (unlike all other pieces). In addition, if the pawn reaches the end of the board it turns into a queen, rook, bishop, or knight (your choice).

Also, the game could end where no one wins, a tie or draw. This can happen in a variety of ways:

• Both sides only have a king left.
• Neither side has any material left that's sufficient to possibly make a checkmate. Any example is one side having a king and knight vs a lone enemy king.
• A position has been repeated three times. This is called a three-fold repetition.
• One player offers a draw and the opponent accepts.
• Stalemate: one side has no moves left because his king is trapped and the rest of his pieces have either been captured off the board or cannot move. This is very similar to a checkmate, except that the trapped king is not being attacked.

I've left out some rules, but this is the meat of it.

Answer 3

Yes, the rules can be explained in a nutshell as follows. It uses some ideas I originally wrote at https://en.wikipedia.org/w/index.php?title=Chess&oldid=649489454.

Chess is a 2 player game. It starts with the pieces arranged like in the following image.

One player moves only white pieces and sits on the side of the board where the white pieces start. The other player moves only black pieces and sits on the side where the black pieces start. Which ever player moves the white pieces starts first.

Chess without some of the extra rules works as follows. Each player on his or her turn can make any move as long as it satisfies the following conditions:

• It's a move of one of the following forms:

  • Normal move

    A normal move is a move where a player moves one piece of their own color under the following conditions:

    • The piece he or she moves is the type of move for that type of piece which is as follows:

      • The king moves one square in any direction.

      • The rook can move any number of squares along any rank or file.

      • The bishop can move any number of squares diagonally.

      • The queen combines the power of the rook and bishop and can move any number of squares along rank, file, or diagonal.

      • The knight moves to any of the closest squares that are not on the same rank, file, or diagonal, thus the move forms an "L"-shape: two squares vertically and one square horizontally, or two squares horizontally and one square vertically.

      • The pawn may move forward to the unoccupied square immediately in front of it on the same file without capturing, or on its first move it may advance two squares along the same file without capturing; or the pawn may capture an opponent's piece on a square diagonally in front of it on an adjacent file, by moving to that square.

    • The piece stays the same type of piece unless it's a pawn moving to the 8th rank in which case it stays the same color and can get promoted to anything except a king. The promotion is not restricted to captured pieces. The pawn must get promoted if it reaches the 8th rank.

    • The piece may not go through another piece unless the former's a knight.

    • The piece captures another piece if it moves there but captures nothing if it moves to an empty square.

    • The piece may not capture a piece that's its own color.

  • Castling move

    A Castling move involves the king and a rook where the king moves two squares along the rank directly towards one of the rooks, then that rook moves over the king to the square that the king crossed over under the following conditions:

    • Neither the king nor the rook it's castling with ever moved before.

    • There are no pieces between the king and the rook it's castling with.

  • En passant move

    When a player moves a pawn 2 squares then on the very next move, the other player moves their pawn diagonally forward 1 square to the square that pawn moved through, capturing it in the process, the latter is said to be doing en passant. Note that the pawn does not move to the square of the pawn it captured in en passant.

  A square is said to be under attack for one player when the other player has a move to that square satisfying the first condition. When the king is under attack, it's said to be in check.

• He or she may not make a move that leaves or puts his or her king in check.

• The king may not castle into check, out of check, or through check.

You win if you check mate your opponent. That is, after your turn, your opponent is in check and doesn't have a legal move. If after your turn, your opponent is not in check and doesn't have a legal move, it's called stalemate. Stalemate is one of the ways for the game to end in a draw.

There are also extra rules. Some of them are very clear and considered a universal rule of chess. Others are unclear how people should play in casual games but are clear in a certain type of tournament. I'm not absolutely completely sure of what they all are. Some of the clear ones are

• The 3 fold repetition rule states that if you go into the same state from the same other state a third time in the game, a draw is declared.
• One player can forfeit the match by resigning. It usually happens when they see that their opponent has a forced win.
• A draw is declared when both players agree to a draw.

Sometimes people also play a casual game of chess with a clock. People also sometimes play a variant of chess like crazyhouse chess but when they're doing that, they're said to be playing a different game which is not chess and are not said to be playing chess. Sometimes one player gives the other player permission to leave and not finish the game. Sometimes one player gives the other player permission to take back moves.

For a certain type of FIDE tournament with a certain rating, the rules are as follows:

• After both players complete 50 moves with nothing getting captured and no pawns moving forward, a player can claim a draw.
• If 75 moves have been completed without anything getting captured or any pawn moving forward, the game must end in a draw unless the last move is a checkmate.
• Both players play with a clock. Each player has 90 minutes for the first 40 moves plus 30 minutes for the rest of the game and an additional 30 seconds per move.

Sources:

• https://en.wikipedia.org/wiki/Chess
• https://en.wikipedia.org/wiki/Fifty-move_rule
• https://www.fide.com/fide/handbook.html?id=39&view=category