X-Git-Url: https://git.auder.net/?a=blobdiff_plain;f=views%2Frules%2FChess960.pug;h=a5c6e6579a720ac30ebaff76a0c53c3364a92a02;hb=2316f8b8248589effc756d5c09c73a1acb431574;hp=8f70e458f53786fd0c25bc1a34f61d9b62775518;hpb=3ad85eac7975eef019f2883fe0be19ed4a646387;p=vchess.git diff --git a/views/rules/Chess960.pug b/views/rules/Chess960.pug index 8f70e458..a5c6e657 100644 --- a/views/rules/Chess960.pug +++ b/views/rules/Chess960.pug @@ -1,3 +1,178 @@ p.boxed - | Orthodox rules (still with shuffled starting position). See for example the - a(href="https://en.wikipedia.org/wiki/Rules_of_chess") Wikipedia page. + | Orthodox rules (with shuffled starting position). + +h3 Basics + +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 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 always 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 pieces 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.e4 means "pawn from e2 to e4". 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: + 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 w 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. + +TODO: diagram let king in check capturing queen, bishop pinned +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 + | fen:nr1kb1r1/ppp3pp/8/2Pp4/8/7P/PP3PP1/1R3KBR: + figcaption Black just played d5 (jump from d7). + +figure.diagram-container + .diagram + | fen:nr1kb1r1/ppp3pp/3P4/8/8/7P/PP3PP1/2KR2BR: + figcaption 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, + 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 why would I stop you? + ☺