| 1 | p.boxed |
| 2 | | Orthodox rules (with shuffled starting position). |
| 3 | |
| 4 | h3 Basics |
| 5 | |
| 6 | p. |
| 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. |
| 12 | |
| 13 | p. |
| 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). |
| 16 | |
| 17 | figure.diagram-container |
| 18 | .diagram |
| 19 | | fen:rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR: |
| 20 | figcaption Standard initial position. |
| 21 | |
| 22 | p. |
| 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. |
| 29 | |
| 30 | h3 Regular moves |
| 31 | |
| 32 | h4 Pawns |
| 33 | |
| 34 | p. |
| 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. |
| 39 | |
| 40 | p. |
| 41 | Pawns capture by moving forward (upper on the board) one square diagonally, |
| 42 | when an enemy piece sits on that square. |
| 43 | |
| 44 | p. |
| 45 | When reaching the last rank, pawns must promote into any (friendly) |
| 46 | other non-royal piece: queen, rook, knight or bishop. |
| 47 | |
| 48 | p. |
| 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". |
| 55 | |
| 56 | figure.diagram-container |
| 57 | .diagram |
| 58 | | fen:k7/8/8/1prp4/1P1P4/8/6P1/7K: |
| 59 | figcaption Possible pawn moves: g3, g4, dxc5, bxc5 |
| 60 | |
| 61 | p |
| 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)") |
| 67 | | Wikipedia page |
| 68 | | for full information on this subject. |
| 69 | |
| 70 | h4 Rooks |
| 71 | |
| 72 | p. |
| 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). |
| 76 | |
| 77 | h4 Knights |
| 78 | |
| 79 | p. |
| 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. |
| 83 | |
| 84 | figure.diagram-container |
| 85 | .diagram |
| 86 | | fen:k7/2p5/5q2/2b5/4N3/2R3r1/3P4/7K f6,d6,c5,f2,g3,g5: |
| 87 | figcaption Possible knight moves from e4. |
| 88 | |
| 89 | h4 Bishops |
| 90 | |
| 91 | p. |
| 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. |
| 94 | |
| 95 | h4 Queen |
| 96 | |
| 97 | p This piece combines the movement of a rook and a bishop, with the same conditions. |
| 98 | |
| 99 | h4 King |
| 100 | |
| 101 | p. |
| 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). |
| 104 | |
| 105 | p. |
| 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: |
| 108 | ul |
| 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. |
| 113 | |
| 114 | p Leaving our king in check after a move is forbidden. |
| 115 | |
| 116 | TODO: diagram let king in check capturing queen, bishop pinned |
| 117 | figure.diagram-container |
| 118 | .diagram |
| 119 | | fen:r6k/4q3/8/8/8/B7/8/K7: |
| 120 | figcaption Bxe7 is illegal (it allows Rxa1). |
| 121 | |
| 122 | h3 Special moves |
| 123 | |
| 124 | p Apart from pawn promotion which has already been introduced, two special moves exist: |
| 125 | ul |
| 126 | li. |
| 127 | castle: if both the king and the right-most (from white player perspective) rook |
| 128 | haven't moved yet, and if nothing stand in the path from king to rook, and if the |
| 129 | squares f1 and g1 are either free or occupied by the king or rook implied, then |
| 130 | the king can go to g1 while the rook moves to f1. Note that since positions are |
| 131 | shuffled one of these two pieces may apparently not move. |
| 132 | The same can be done on the other side (left-most rook), and end squares are c1 |
| 133 | for king and d1 for rook. The former is small castle, and the latter large castle. |
| 134 | Notation: small castle writes "0-0" while large castle is "0-0-0". |
| 135 | li. |
| 136 | en-passant: after a pawn has jumped two squares, if an enemy pawn stands just next |
| 137 | to it then it can capture the jumping pawn "en passant", exactly as if it had |
| 138 | advanced only one square. The move is noted as usual, but with "e.p." in the end |
| 139 | to indicate the special move. |
| 140 | The capture is possible only right after the pawn jump: not later in the game. |
| 141 | |
| 142 | figure.diagram-container |
| 143 | .diagram.diag12 |
| 144 | | fen:nr1kb1r1/ppp3pp/8/2Pp4/8/7P/PP3PP1/1R3KBR: |
| 145 | .diagram.diag22 |
| 146 | | fen:nr1kb1r1/ppp3pp/3P4/8/8/7P/PP3PP1/2KR2BR: |
| 147 | figcaption. |
| 148 | Left: black just played d5 (jump from d7). |
| 149 | Right: after cxd6 e.p. and 0-0-0. |
| 150 | |
| 151 | h3 End of the game |
| 152 | |
| 153 | p. |
| 154 | The best-known way to end a game is by "checkmating" the enemy king. |
| 155 | This means that you end a move in a situation where the king can be captured, |
| 156 | and your opponent has no way to avoid the capture. |
| 157 | The checkmating player has one point and the other zero, so the score writes 1-0 |
| 158 | or 0-1 depending if white pieces or black pieces mated. |
| 159 | |
| 160 | figure.diagram-container |
| 161 | .diagram |
| 162 | | fen:rnbqkbnr/ppp2Qpp/2np4/4p3/2B1P3/8/PPPP1PPP/RNB1K1NR: |
| 163 | figcaption Famous mating pattern: 1-0 |
| 164 | |
| 165 | p All other ways to end the game lead to a draw (1/2-1/2): nobody wins: |
| 166 | ul |
| 167 | li when a player has no legal move but is not under check, |
| 168 | li. |
| 169 | when a position is repeated three times with the same castling right and |
| 170 | same player in turn, |
| 171 | li when 50 moves are played without pawn movement or capture. |
| 172 | p. |
| 173 | Note: this last way to end a game is not implemented, because it quite seldom occurs, |
| 174 | does not generalize so well to variants (it depends), and more important because |
| 175 | games played on this website are not official tournament games. If you feel like |
| 176 | manoeuvring for 200 moves and your opponent isn't bored, then why would I stop you? :) |