| 1 | p.boxed |
| 2 | | Most pieces look the same but behave very differently. |
| 3 | | They generally move like an orthodox queen, |
| 4 | | but capturing rules are complex. |
| 5 | |
| 6 | h3 Specifications |
| 7 | |
| 8 | ul |
| 9 | li Chessboard: standard. |
| 10 | li Material: "standard". |
| 11 | li Non-capturing moves: often like queen. |
| 12 | li Special moves: none. |
| 13 | li Captures: very special. |
| 14 | li End of game: standard; see below. |
| 15 | |
| 16 | h4 Pieces names |
| 17 | |
| 18 | p Pieces names refer to the way they capture, which is described later. |
| 19 | ul |
| 20 | li Pawn : pawn or pincer |
| 21 | li Rook : coordinator |
| 22 | li Knight : long leaper |
| 23 | li Bishop : chameleon |
| 24 | li Queen : withdrawer |
| 25 | li King : king (same behavior as in standard chess) |
| 26 | p. |
| 27 | Besides, a new piece is introduced: the immobilizer, represented by the letter 'm' |
| 28 | in FEN diagrams and PGN games. It is represented by an upside-down rook: |
| 29 | |
| 30 | figure.diagram-container |
| 31 | .diagram |
| 32 | | fen:8/8/4m3/8/8/8/3M4/8: |
| 33 | figcaption Immobilizers on d2 and e6. |
| 34 | |
| 35 | h3 Non-capturing moves |
| 36 | |
| 37 | p |
| 38 | | Pawns move as orthodox rooks, and the king moves as usual, |
| 39 | | one square in any direction. |
| 40 | | All other pieces move like an orthodox queen. |
| 41 | |
| 42 | p. |
| 43 | When a piece is adjacent to an enemy immobilizer, it cannot move unless |
| 44 | the enemy immobilizer is adjacent to a friendly immobilizer or chameleon |
| 45 | (cancelling the powers of the opponent's immobilizer). |
| 46 | p |
| 47 | | Note : this corresponds to the "pure rules" described on |
| 48 | a(href="http://www.inference.org.uk/mackay/ultima/ultima.html") this page |
| 49 | | , which slightly differ from the initial rules. |
| 50 | | The aim is to get rid of the weird suicide rule by weakening the immobilizers lock. |
| 51 | | In particular, in the original rules two adjacent immobilizer are stuck forever |
| 52 | | until one is captured. Note that it's still the case if all chameleons disappeared. |
| 53 | |
| 54 | h3 Capturing moves |
| 55 | |
| 56 | p |
| 57 | | Easy case first: the king captures as usual, by moving onto an adjacent square |
| 58 | | occupied by an enemy piece. But this is the only piece following orthodox rules, |
| 59 | | and also the only one which captures by moving onto an occupied square. |
| 60 | | All other pieces capture passively: they land on a free square and captured |
| 61 | | units are determined by some characteristics of the movement. |
| 62 | |
| 63 | p Note 1: the immobilizer does not capture. |
| 64 | |
| 65 | p. |
| 66 | Note 2: for passive captures, a 'X' is added at the end of the move notation, |
| 67 | to indicate that something was taken (replaying the game is necessary to know where). |
| 68 | |
| 69 | h4 Pawns/Pincers |
| 70 | |
| 71 | p. |
| 72 | If at the end of its movement a pawn is horizontally or vertically adjacent to an |
| 73 | enemy piece, which itself is next to a friendly piece (in the same direction), |
| 74 | the "pinced" unit is removed from the board. |
| 75 | |
| 76 | figure.diagram-container |
| 77 | .diagram |
| 78 | | fen:7k/5ppp/2N5/2n5/3rB3/8/PPP5/K7: |
| 79 | figcaption 1.Pc2c4 captures both coordinator and long leaper. |
| 80 | |
| 81 | h4 Coordinators (rooks) |
| 82 | |
| 83 | p. |
| 84 | Imagine that rook and king are two corners of a rectangle (this works if these |
| 85 | two pieces are unaligned). |
| 86 | If at the end of a rook move an enemy piece stands in any of the two remaining |
| 87 | corners, it is captured. |
| 88 | |
| 89 | figure.diagram-container |
| 90 | .diagram |
| 91 | | fen:8/2b4K/2q5/3p1N1p/8/8/2R5/k7: |
| 92 | figcaption 1.Rc5 captures on c7 and h5. |
| 93 | |
| 94 | h4 Long leapers (knights) |
| 95 | |
| 96 | p. |
| 97 | A knight captures exactly as a queen in international draughts game: by jumping |
| 98 | over its enemies, as many times as it can/want but always in the same direction. |
| 99 | In this respect it is less powerful than a draughts' queen: |
| 100 | on the following diagram c8 or f6 cannot be captured. |
| 101 | However, the knight does not have to maximize the number of captured units |
| 102 | (as is the case in draughts). |
| 103 | |
| 104 | figure.diagram-container |
| 105 | .diagram |
| 106 | | fen:2n4k/3r4/5b2/3p4/1m6/3b4/3N4/K7 w d4,d6,d8,a5: |
| 107 | figcaption All marked squares captures are playable from d2. |
| 108 | |
| 109 | h4 Withdrawer (queen) |
| 110 | |
| 111 | p. |
| 112 | The queen captures by moving away from an adjacent enemy piece, in the opposite |
| 113 | direction (only the long leaper can jump). |
| 114 | |
| 115 | figure.diagram-container |
| 116 | .diagram |
| 117 | | fen:7k/8/8/3Qr3/8/8/8/K7 w a5,b5,c5: |
| 118 | figcaption 1.Qa5, 1.Qb5 or 1.Qc5 captures the black rook. |
| 119 | |
| 120 | h4 Chameleon (bishop) |
| 121 | |
| 122 | p The chameleon captures pieces in the way they would capture. So, it |
| 123 | ul |
| 124 | li pinces pawns, |
| 125 | li withdraws from withdrawers, |
| 126 | li leaps over long leapers, |
| 127 | li coordinates coordinators. |
| 128 | p ...and these captures can be combined. |
| 129 | |
| 130 | figure.diagram-container |
| 131 | .diagram |
| 132 | | fen:7k/8/8/r3pP2/2n5/8/B7/K7 w a5,c4,e5: |
| 133 | figcaption 1.Bd5 captures all marked pieces. |
| 134 | |
| 135 | p. |
| 136 | Besides, chameleon immobilizes immobilizers (but cannot capture them since they |
| 137 | do not capture). |
| 138 | |
| 139 | p. |
| 140 | A chameleon captures the king in the same way the king captures, which means that |
| 141 | a chameleon adjacent to a king gives check. |
| 142 | |
| 143 | h3 End of the game |
| 144 | |
| 145 | p. |
| 146 | Checkmate or stalemate as in standard chess. Note however that checks are more |
| 147 | difficult to see, because of the exotic capturing rules. For example, on the |
| 148 | following diagram the white king cannot move to the marked squares because then |
| 149 | the black pawn could capture by moving next to it. |
| 150 | |
| 151 | figure.diagram-container |
| 152 | .diagram |
| 153 | | fen:7k/8/8/p4r/4K3/8/8/8 w e5: |
| 154 | figcaption 1.Ke5 is impossible |
| 155 | |
| 156 | h3 Credits |
| 157 | |
| 158 | p. |
| 159 | A good starting point is the |
| 160 | #[a(href="https://en.wikipedia.org/wiki/Baroque_chess") Wikipedia page], |
| 161 | which also gives pointers to other interesting pages (including chessvariants.com, |
| 162 | as usual). |