2 | Orthodox rules (with shuffled starting position).
7 Chess is played between two players, one moving the white pieces and the other
8 the black pieces. A "move" consists of a piece's movement on the board.
9 White and black moves alternate until a specific situation occurs (checkmate,
10 stalemate, or draw criteria met; this is detailed later).
11 White pieces' player always make the first move.
14 Each piece has a particular way to move, but almost always captures by moving to an
15 occupied square (with only one exception, detailed later).
17 figure.diagram-container
19 | fen:rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR:
20 figcaption Standard initial position.
23 Board coordinates: squares are identified by a couple (letter, number).
24 The letter starts from 'a' and indicates the column, while the number starts
25 at 1 and indicates the row.
26 Since the chessboard is 64 squares, 8x8, this results in a coordinates system
27 from a1 to h8. 'a1' is the bottom left corner square from the white pieces
28 player perspective, while 'h8' is in the upper right corner.
35 They are the weakest units on board, but the most complex to move.
36 From their initial rank they can either jump two squares forward (vertically),
37 or advance only one square in this same direction. After that first move they
38 only advance one square at a time, vertically, moving up.
41 Pawns capture by moving forward (upper on the board) one square diagonally,
42 when an enemy piece sits on that square.
45 When reaching the last rank, pawns must promote into any (friendly)
46 other non-royal piece: queen, rook, knight or bishop.
49 Moves notations: "pawn" is implicit, so for a simple move we only write the
50 destination square (because only one pawn at most can move forward to a specific
51 square). Thus, 1.e5 means "pawn from e4 to e5". However, in case of captures
52 the situation could be ambiguous (two pawns on the same rank), so the column
53 is specified too: "fxe6" (for example).
54 As you can see capture is marked by a cross symbol: "x".
56 figure.diagram-container
58 | fen:k7/8/8/1prp4/1P1P4/8/6P1/7K:
59 figcaption Possible pawn moves: g3, g4, dxc5, bxc5
62 | For a piece movement, we just prepend the upper-case piece initial before the
63 | previously described notation. A rook taking something on f3 square writes:
64 | Rxf3. There are rules for ambiguous situation, but discussing them now would
65 | be too far off-topic. Please visit for example the
66 a(href="https://en.wikipedia.org/wiki/Algebraic_notation_(chess)")
68 | for full information on this subject.
73 They move either horizontally or vertically, as far as they want while the path
74 is free of pieces. If this path ends with an enemy piece, it can a priori be captured
75 (a priori because if the move ends up with the king in check, then it's illegal).
80 They are the only units able to jump over other pieces (without capturing them).
81 They do "L" moves: two squares in one direction (horizontally or vertically),
82 and then one square in an orthogonal direction.
84 figure.diagram-container
86 | fen:k7/2p5/5q2/2b5/4N3/2R3r1/3P4/7K f6,d6,c5,f2,g3,g5:
87 figcaption Possible knight moves from e4.
92 They move diagonally, as far as they want while the path is free of pieces.
93 If this path ends with an enemy piece, it can a priori be captured.
97 p This piece combines the movement of a rook and a bishop, with the same conditions.
102 This piece moves like a queen, but only by one square at a time. The final square
103 must be either vacant or occupied by an enemy piece (therefore captured).
106 The king cannot be captured, but a move may ends up attacking enemy's king.
107 It is said to be "under check" (or "in check") and the opponent must either:
109 li move the king to a safe square, or
110 li capture the attacker, or
111 li intercept the attacking line.
112 p Depending on the situation one or more of these counter-measures could be impossible.
114 p Leaving our king in check after a move is forbidden.
116 figure.diagram-container
118 | fen:r6k/4q3/8/8/8/B7/8/K7:
119 figcaption Bxe7 is illegal (it allows Rxa1).
123 p Apart from pawn promotion which has already been introduced, two special moves exist:
126 castle: if both the king and the right-most (from white player perspective) rook
127 haven't moved yet, and if nothing stand in the path from king to rook, and if the
128 squares f1 and g1 are either free or occupied by the king or rook implied, then
129 the king can go to g1 while the rook moves to f1. Note that since positions are
130 shuffled one of these two pieces may apparently not move.
131 The same can be done on the other side (left-most rook), and end squares are c1
132 for king and d1 for rook. The former is small castle, and the latter large castle.
133 Notation: small castle writes "0-0" while large castle is "0-0-0".
135 en-passant: after a pawn has jumped two squares, if an enemy pawn stands just next
136 to it then it can capture the jumping pawn "en passant", exactly as if it had
137 advanced only one square. The move is noted as usual, but with "e.p." in the end
138 to indicate the special move.
139 The capture is possible only right after the pawn jump: not later in the game.
141 figure.diagram-container
143 | fen:nr1kb1r1/ppp3pp/8/2Pp4/8/7P/PP3PP1/1R3KBR:
145 | fen:nr1kb1r1/ppp3pp/3P4/8/8/7P/PP3PP1/2KR2BR:
147 Left: black just played d5 (jump from d7).
148 Right: after cxd6 e.p. and 0-0-0.
153 The best-known way to end a game is by "checkmating" the enemy king.
154 This means that you end a move in a situation where the king can be captured,
155 and your opponent has no way to avoid the capture.
156 The checkmating player has one point and the other zero, so the score writes 1-0
157 or 0-1 depending if white pieces or black pieces mated.
159 figure.diagram-container
161 | fen:rnbqkbnr/ppp2Qpp/2np4/4p3/2B1P3/8/PPPP1PPP/RNB1K1NR:
162 figcaption Famous mating pattern: 1-0
164 p All other ways to end the game lead to a draw (1/2-1/2); nobody wins:
166 li when a player has no legal move but is not under check (stalemate),
168 when a position is repeated three times with the same castling right and
170 li when 50 moves are played without pawn movement or capture.
172 Note: this last way to end a game is not implemented, because it quite seldom occurs,
173 does not generalize so well to variants (it depends), and more important because
174 games played on this website are not official tournament games. If you feel like
175 manoeuvring for 200 moves and your opponent isn't bored, then why would I stop you? :)