2 | The capture of an enemy piece produces a new "checkered" piece belonging
5 figure.showPieces.text-center
6 img(src="/images/pieces/Checkered/cp.svg")
7 img(src="/images/pieces/Checkered/cr.svg")
8 img(src="/images/pieces/Checkered/cn.svg")
9 img(src="/images/pieces/Checkered/cb.svg")
10 img(src="/images/pieces/Checkered/cq.svg")
11 figcaption Checkered pieces, born after captures.
13 p Note: the initial French name for this variant is "l'Échiqueté".
15 p The game potentially evolves in two stages.
17 h2.stageDelimiter Stage 1
23 | Each capture produces a new piece, taking on nature of
24 | the capturing or captured one.
26 | The new piece arising from a capture has a new color:
27 | "checkered", as illustrated above.
29 | All checkered pieces belong to the player in turn and can
30 | capture the opponents pieces.
35 A non-capturing checkered move cannot be "undone" right after since
36 this would repeat the same position.
37 li Checkered pieces cannot be captured.
39 figure.diagram-container
41 | fen:2kr4/pp6/2p5/4ss1r/1P2ns1P/2Np4/P1P1P1BP/R2o1RK1:
43 Black plays Rxh4=P. (Checkered pawn to) h5 is allowed then,
44 because piece's nature changed.
50 Pawns can jump two squares only from their initial rank, and only once in
51 the game: a checkered pawn returning on the pawns' start rank cannot jump.
54 A pawn captured on its starting square (thus becoming "checkered") keeps
55 the right to advance two squares.
57 Checkered pawns cannot capture en passant, because while the pawn was
58 "passing" they were of the same color.
60 h3 Stalemate or checkmate?
63 The following diagram seems to show a mating pattern, but the king if
64 "attacked" by a checkered pawn – which still belongs to white.
65 Therefore, it can be considered that it's not really a check because
66 white is unable to "give back the turn".
67 Without the black bishop on a7 it would be mate (without debate), because
68 the king could virtually go to g1 before being captured by the
71 figure.diagram-container
73 | fen:7k/b5pp/8/8/8/8/6ss/7K:
74 figcaption After 1...g2+(#?)
77 The interface considers that it's mate in both cases, following the idea
78 "it's checkmate if we cannot move, and the opponent on its turn could
79 take the king" (maybe after an impossible move).
81 h2.stageDelimiter Stage 2
84 During the game one of the two players can decide to take control of the
86 They thus become autonomous and vulnerable to being captured - stage 2
87 begins. The other player is in charge of both the white and black pieces, and
88 tries to eliminate checkered pieces.
89 The checkered side wins by checkmating either the white or black king.
92 To take the checkered pieces, play a move that "takes opponent's king" with
93 your king, and then execute a move. This is possible only if no such move
96 h4 Variant of stage 2 (unimplemented)
98 An observer could decide to join the game by taking the checkered pieces
100 It then becomes a chess game with three players, with some subtelties to be
101 resolved. It was tested in some (real life) games organised by the variant
106 p Checkered pawns can...
108 li move and capture in either direction;
110 li be promoted on either the first or eighth row.
116 The rules of Checkered Chess were thought up by Patrick Bernier and
117 developed with the help of Benjamin Auder around 2011-2012.
119 Thanks also to Olive Martin, Christian Poisson, Bevis Martin, Laurent
120 Nouhaud and Frédéric Fradet.