Simplified underCheck / getCheckSquares logic. Debugging Berolina

[vchess.git] / views / rules / Checkered / en.pug

p.boxed
	| The capture of an enemy piece produces a new "checkered" piece belonging
	| to both players.

figure.showPieces.center-align
	img(src="/images/tmp_checkered/cp.png")
	img(src="/images/tmp_checkered/cr.png")
	img(src="/images/tmp_checkered/cn.png")
	img(src="/images/tmp_checkered/cb.png")
	img(src="/images/tmp_checkered/cq.png")
	img(src="/images/tmp_checkered/no_ck.png")
	figcaption Checkered pieces, born after captures.

h3 Specifications

ul
	li Chessboard: standard.
	li Material: additional checkered pieces.
	li Non-capturing moves: standard; see below.
	li Special moves: standard; see below.
	li Captures: standard; see below.
	li End of game: standard.

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.

span 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 Pions

ul
	li.
		Pawns can jump two squares only from their initial rank, and only once in the game:
		a checkered pawn returning on the pawns' start rank cannot jump. However:
	li.
		A pawn captured on its starting square (thus becoming "checkered") keeps the
		right to advance two squares.
	li.
		Checkered pawns cannot capture en passant, because while the pawn was "passing"
		they were of the same color.

h2.stageDelimiter Stage 2

p.warn This stage is not (and probably will never be) implemented.

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.

h4 Variant of stage 2
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 creator.

h3 Special moves

span 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.
	li.
		Thanks also to Olive Martin, Christian Poisson, Bevis Martin, Laurent Nouhaud
		and Frédéric Fradet.