+p.boxed
+ | The capture of an enemy piece produces a new "checkered" piece belonging
+ | to both players.
+
+figure.showPieces.text-center
+ img(src="/images/pieces/Checkered/cp.svg")
+ img(src="/images/pieces/Checkered/cr.svg")
+ img(src="/images/pieces/Checkered/cn.svg")
+ img(src="/images/pieces/Checkered/cb.svg")
+ img(src="/images/pieces/Checkered/cq.svg")
+ figcaption Checkered pieces, born after captures.
+
+p Note: the initial French name for this variant is "l'Échiqueté".
+
+p The game potentially evolves in two stages.
+
+h2.stageDelimiter Stage 1
+
+h3 Basics
+
+ol
+ li
+ | Each capture produces a new piece, taking on nature of
+ | the capturing or captured one.
+ li
+ | The new piece arising from a capture has a new color:
+ | "checkered", as illustrated above.
+ li
+ | All checkered pieces belong to the player in turn and can
+ | capture the opponents pieces.
+
+p Remarks:
+ul
+ li.
+ A non-capturing checkered move cannot be "undone" right after since
+ this would repeat the same position.
+ li Checkered pieces cannot be captured.
+
+figure.diagram-container
+ .diagram
+ | fen:2kr4/pp6/2p5/4ss1r/1P2ns1P/2Np4/P1P1P1BP/R2o1RK1:
+ figcaption.
+ Black plays Rxh4=P. (Checkered pawn to) h5 is allowed then,
+ because piece's nature changed.
+
+h3 Pawns
+
+ul
+ li.
+ Pawns can jump two squares only from their initial rank, and only once in
+ the game. A checkered pawn keeps this right if the starting pawn
+ did not use it.
+ li.
+ Checkered pawns cannot capture en passant, because while the pawn was
+ "passing" they were of the same color.
+
+h3 Stalemate or checkmate?
+
+p.
+ The following diagram seems to show a mating pattern, but the king if
+ "attacked" by a checkered pawn – which still belongs to white.
+ Therefore, it can be considered that it's not really a check because
+ white is unable to "give back the turn".
+ Without the black bishop on a7 it would be mate (without debate), because
+ the king could virtually go to g1 before being captured by the
+ chameleon pawn.
+
+figure.diagram-container
+ .diagram
+ | fen:7k/b5pp/8/8/8/8/6ss/7K:
+ figcaption After 1...g2+(#?)
+
+p.
+ The interface considers that it's mate in both cases, following the idea
+ "it's checkmate if we cannot move, and the opponent on its turn could
+ take the king" (maybe after an impossible move).
+
+h2.stageDelimiter Stage 2
+
+p.italic.
+ This stage can be disabled by unselecting "With switch" at game creation.
+
+p.
+ During the game one of the two players can decide to take control of the
+ checkered pieces.
+ They thus become autonomous and vulnerable to being captured - stage 2
+ begins. The other player is in charge of both the white and black pieces, and
+ tries to eliminate checkered pieces.
+ The checkered side wins by checkmating either the white or black king.
+
+p.
+ To take the checkered pieces, play a move that "takes opponent's king" with
+ your king, and then execute a move. This is possible only if no such move
+ can capture a king.
+
+h4 Variant of stage 2 (unimplemented)
+p.
+ An observer could decide to join the game by taking the checkered pieces
+ at any moment.
+ It then becomes a chess game with three players, with some subtelties to be
+ resolved. It was tested in some (real life) games organised by the variant
+ inventor.
+
+h3 Special moves
+
+p Checkered pawns can...
+ul
+ li move and capture in either direction;
+ li take en passant,
+ li be promoted on either the first or eighth row.
+
+h3 Credits
+
+ul
+ li.
+ The rules of Checkered Chess were thought up by Patrick Bernier and
+ developed with the help of Benjamin Auder around 2011-2012.
+ li.
+ Thanks also to Olive Martin, Christian Poisson, Bevis Martin, Laurent
+ Nouhaud and Frédéric Fradet.