New variant idea
[xogo.git] / variants / Checkered / complete_rules.html
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1<!doctype html>
2<html>
3<head>
4 <title>Checkered Rules</title>
5 <link href="/common.css" rel="stylesheet"/>
6 <link href="/variants/Checkered/style.css" rel="stylesheet"/>
7</head>
8<body>
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9<div class="full-rules">
10<h1>Checkered Rules</h1>
11
12<div>
13<p class="boxed">
14 The capture of an enemy piece produces a new "checkered" piece belonging
15 to both players.
16</p>
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17<figure class="show-pieces">
18 <img src="/pieces/Checkered/cp.svg"/>
19 <img src="/pieces/Checkered/cr.svg"/>
20 <img src="/pieces/Checkered/cn.svg"/>
21 <img src="/pieces/Checkered/cb.svg"/>
22 <img src="/pieces/Checkered/cq.svg"/>
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23 <figcaption>Checkered pieces, born after captures.</figcaption>
24</figure>
25<p>Note: the initial French name for this variant is "l'Échiqueté".</p>
26<p>The game potentially evolves in two stages.</p>
27</div>
28
29<div>
30<h2 class="stageDelimiter">Stage 1</h2>
31<h3>Basics</h3>
32<ol>
33 <li>
34 Each capture produces a new piece, taking on nature of
35 the capturing or captured one.
36 </li>
37 <li>
38 The new piece arising from a capture has a new color:
39 "checkered", as illustrated above.
40 </li>
41 <li>
42 All checkered pieces belong to the player in turn and can
43 capture the opponents pieces.
44 </li>
45</ol>
46<p>Remarks:</p>
47<ul>
48 <li>
49 A non-capturing checkered move cannot be "undone" right after since
50 this would repeat the same position.
51 </li>
52 <li>Checkered pieces cannot be captured.</li>
53</ul>
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54<figure>
55 <div class="diag"
56 data-fen='2kr4/pp6/2p5/4ss1r/1P2ns1P/2Np4/P1P1P1BP/R2o1RK1'>
57 </div>
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58 <figcaption>
59 Black plays Rxh4=P. (Checkered pawn to) h5 is allowed then,
60 because piece's nature changed.
61
62 </figcaption>
63</figure>
64<h3>Pawns</h3>
65<ul>
66 <li>
67 Pawns can jump two squares only from their initial rank, and only once in
68 the game. A checkered pawn keeps this right if the starting pawn
69 did not use it.
70 </li>
71 <li>
72 Checkered pawns cannot capture en passant, because while the pawn was
73 "passing" they were of the same color.
74
75 </li>
76</ul>
77<h3>Stalemate or checkmate?</h3>
78<p>
79 The following diagram seems to show a mating pattern, but the king if
80 "attacked" by a checkered pawn &ndash; which still belongs to white.
81 Therefore, it can be considered that it's not really a check because
82 white is unable to "give back the turn".
83 Without the black bishop on a7 it would be mate (without debate), because
84 the king could virtually go to g1 before being captured by the
85 chameleon pawn.
86
87</p>
88<figure>
89 <div class="diag"
90 data-fen='7k/b5pp/8/8/8/8/6ss/7K w 4 {"flags":"88880000000000000011"}'>
91 </div>
92 <figcaption>After 1...g2+(#?).</figcaption>
93</figure>
94<p>
95 The interface considers that it's mate in both cases, following the idea
96 "it's checkmate if we cannot move, and the opponent on its turn could
97 take the king" (maybe after an impossible move).
98
99</p>
100</div>
101
102<div>
103<h2 class="stageDelimiter">Stage 2</h2>
104<p class="italic">
105 This stage can be disabled by unselecting "With switch" at game creation.
106</p>
107<p>
108 During the game one of the two players can decide to take control of the
109 checkered pieces.
110 They thus become autonomous and vulnerable to being captured - stage 2
111 begins. The other player is in charge of both the white and black pieces, and
112 tries to eliminate checkered pieces.
113 The checkered side wins by checkmating either the white or black king.
114</p>
115<p>
116 To take the checkered pieces, play a move that "takes opponent's king" with
117 your king, and then execute a move. This is possible only if no such move
118 can capture a king.
119</p>
120<h4>Variant of stage 2 (unimplemented)</h4>
121<p>
122 An observer could decide to join the game by taking the checkered pieces
123 at any moment.
124 It then becomes a chess game with three players, with some subtelties to be
125 resolved. It was tested in some (real life) games.
126</p>
127<h3>Special moves</h3>
128<p>Checkered pawns can...</p>
129<ul>
130 <li>move and capture in either direction;</li>
131 <li>take en passant,</li>
132 <li>be promoted on either the first or eighth row.</li>
133</ul>
134</div>
135
136<div>
137<h3>Credits</h3>
138<ul>
139 <li>
140 The rules of Checkered Chess were thought up by Patrick Bernier and
141 developed with the help of Benjamin Auder around 2011-2012.
142 </li>
143 <li>
144 Thanks also to Olive Martin, Christian Poisson, Bevis Martin, Laurent
145 Nouhaud and Frédéric Fradet.
146 </li>
147</ul>
148</div>
149
150</body>
151<script src="/utils/drawDiagrams.js"></script>
152<script>fenToDiag("Checkered");</script>
153</html>