+++ /dev/null
-p.boxed
- | Orthodox rules (with shuffled starting position).
-
-p.
- Chess is played between two players, one moving the white pieces and the
- other the black pieces. A "move" consists of a piece's movement on the board.
- White and black moves alternate until a specific situation occurs (checkmate,
- stalemate, or draw criteria met; this is detailed later).
- White pieces' player always make the first move.
-
-p.
- Each piece has a particular way to move, but almost always captures by moving
- to an occupied square (with only one exception, detailed later).
-
-figure.diagram-container
- .diagram
- | fen:rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR:
- figcaption Standard initial position.
-
-p.
- Board coordinates: squares are identified by a couple (letter, number).
- The letter starts from 'a' and indicates the column, while the number starts
- at 1 and indicates the row.
- Since the chessboard is 64 squares, 8x8, this results in a coordinates system
- from a1 to h8. 'a1' is the bottom left corner square from the white pieces
- player perspective, while 'h8' is in the upper right corner.
-
-h3 Regular moves
-
-h4 Pawns
-
-p.
- They are the weakest units on board, but the most complex to move.
- From their initial rank they can either jump two squares forward
- (vertically), or advance only one square in this same direction. After that
- first move they only advance one square at a time, vertically, moving up.
-
-p.
- Pawns capture by moving forward (upper on the board) one square diagonally,
- when an enemy piece sits on that square.
-
-p.
- When reaching the last rank, pawns must promote into any (friendly)
- other non-royal piece: queen, rook, knight or bishop.
-
-p.
- Moves notations: "pawn" is implicit, so for a simple move we only write the
- destination square (because only one pawn at most can move forward to a
- specific square). Thus, 1.e5 means "pawn from e4 to e5". However, in case of
- captures the situation could be ambiguous (two pawns on the same rank), so
- the column is specified too: "fxe6" (for example).
- As you can see capture is marked by a cross symbol: "x".
-
-figure.diagram-container
- .diagram
- | fen:k7/8/8/1prp4/1P1P4/8/6P1/7K g3,g4,c5:
- figcaption Possible pawn moves: g3, g4, dxc5, bxc5
-
-p
- | For a piece movement, we just prepend the upper-case piece initial before
- | the previously described notation. A rook taking something on f3 square
- | writes: Rxf3. There are rules for ambiguous situation, but discussing them
- | now would be too far off-topic. Please visit for example the
- a(href="https://en.wikipedia.org/wiki/Algebraic_notation_(chess)")
- | Wikipedia page
- | for full information on this subject.
-
-h4 Rooks
-
-p.
- They move either horizontally or vertically, as far as they want while the
- path is free of pieces. If this path ends with an enemy piece, it can a
- priori be captured (a priori because if the move ends up with the king in
- check, then it's illegal).
-
-h4 Knights
-
-p.
- They are the only units able to jump over other pieces (without capturing
- them). They do "L" moves: two squares in one direction (horizontally or
- vertically), and then one square in an orthogonal direction.
-
-figure.diagram-container
- .diagram
- | fen:k7/2p5/5q2/2b5/4N3/2R3r1/3P4/7K f6,d6,c5,f2,g3,g5:
- figcaption Possible knight moves from e4.
-
-h4 Bishops
-
-p.
- They move diagonally, as far as they want while the path is free of pieces.
- If this path ends with an enemy piece, it can a priori be captured.
-
-h4 Queen
-
-p.
- This piece combines the movement of a rook and a bishop, with the same
- conditions.
-
-h4 King
-
-p.
- This piece moves like a queen, but only by one square at a time. The final
- square must be either vacant or occupied by an enemy piece (therefore
- captured).
-
-p.
- The king cannot be captured, but a move may ends up attacking enemy's king.
- It is said to be "under check" (or "in check") and the opponent must either:
-ul
- li move the king to a safe square, or
- li capture the attacker, or
- li intercept the attacking line.
-p.
- Depending on the situation one or more of these counter-measures could be
- impossible.
-
-p Leaving our king in check after a move is forbidden.
-
-figure.diagram-container
- .diagram
- | fen:r6k/4q3/8/8/8/B7/8/K7:
- figcaption Bxe7 is illegal (it allows Rxa1).
-
-h3 Special moves
-
-p.
- Apart from pawn promotion which has already been introduced, two special
- moves exist:
-ul
- li.
- castle: if both the king and the right-most (from white player perspective)
- rook haven't moved yet, and if nothing stand in the path from king to rook,
- and if the squares f1 and g1 are either free or occupied by the king or
- rook implied, then the king can go to g1 while the rook moves to f1. Note
- that since positions are shuffled one of these two pieces may apparently
- not move. The same can be done on the other side (left-most rook), and end
- squares are c1 for king and d1 for rook. The former is small castle, and
- the latter large castle.
- Notation: small castle writes "0-0" while large castle is "0-0-0".
- li.
- en-passant: after a pawn has jumped two squares, if an enemy pawn stands
- just next to it then it can capture the jumping pawn "en passant", exactly
- as if it had advanced only one square. The move is noted as usual, but
- with "e.p." in the end to indicate the special move. The capture is
- possible only right after the pawn jump: not later in the game.
-
-figure.diagram-container
- .diagram.diag12
- | fen:nr1kb1r1/ppp3pp/8/2Pp4/8/7P/PP3PP1/1R3KBR:
- .diagram.diag22
- | fen:nr1kb1r1/ppp3pp/3P4/8/8/7P/PP3PP1/2KR2BR:
- figcaption.
- Left: black just played d5 (jump from d7).
- Right: after cxd6 e.p. and 0-0-0.
-
-h3 End of the game
-
-p.
- The best-known way to end a game is by "checkmating" the enemy king.
- This means that you end a move in a situation where the king can be captured,
- and your opponent has no way to avoid the capture.
- The checkmating player has one point and the other zero, so the score writes
- 1-0 or 0-1 depending if white pieces or black pieces mated.
-
-figure.diagram-container
- .diagram
- | fen:rnbqkbnr/ppp2Qpp/2np4/4p3/2B1P3/8/PPPP1PPP/RNB1K1NR:
- figcaption Famous mating pattern: 1-0
-
-p All other ways to end the game lead to a draw (1/2-1/2); nobody wins:
-ul
- li when a player has no legal move but is not under check (stalemate),
- li.
- when a position is repeated three times with the same castling right and
- same player in turn,
- li when 50 moves are played without pawn movement or capture.
-p.
- Note: this last way to end a game is not implemented, because it quite seldom
- occurs, does not generalize so well to variants (it depends), and more
- important because games played on this website are not official tournament
- games. If you feel like manoeuvring for 200 moves and your opponent isn't
- bored, then keep going :)
projects / vchess.git / blobdiff