X-Git-Url: https://git.auder.net/?a=blobdiff_plain;f=views%2Frules%2FUltima.pug;h=c79acc35ddc584b67891de8148f618ca66d5e313;hb=15c1295af871a5f416b0e5b43127512c8095497a;hp=423ba5d68ef775939849b42bc9ecc6bebf49cff9;hpb=331fc58c932d6d7055b202d0c6dc0d77212a89f8;p=vchess.git

diff --git a/views/rules/Ultima.pug b/views/rules/Ultima.pug
index 423ba5d6..c79acc35 100644
--- a/views/rules/Ultima.pug
+++ b/views/rules/Ultima.pug
@@ -13,18 +13,141 @@ ul
 	li Captures: very special.
 	li End of game: standard; see below.
 
+h4 Pieces names
+
+p Pieces names refer to the way they capture, which is described later.
+ul
+	li Pawn : pawn or pincer
+	li Rook : coordinator
+	li Knight : long leaper
+	li Bishop : chameleon
+	li Queen : withdrawer
+	li King : king (same behavior as in standard chess)
+p.
+	Besides, a new piece is introduced: the immobilizer, represented by the letter 'm'
+	in FEN diagrams and PGN games. It is represented by an upside-down rook:
+
+figure.diagram-container
+	.diagram
+		| fen:8/8/4m3/8/8/8/3M4/8:
+	figcaption Immobilizers on d2 and e6.
+
 h3 Non-capturing moves
 
-// TODO: short paragraph, only the king moves like an orthodox king
-// Consider these rules modifications: http://www.inference.org.uk/mackay/ultima/ultima.html
+p
+	| Pawns move as orthodox rooks, and the king moves as usual,
+	| one square in any direction.
+	| All other pieces move like an orthodox queen.
+
+p When a piece is adjacent to an enemy immobilizer, it cannot move unless
+ul
+	li it is an immobilizer or a chameleon; or
+	li.
+		the enemy immobilizer is adjacent to a friendly immobilizer or chameleon
+		(cancelling the powers of the opponent's immobilizer)
+p
+	| Note : this corresponds to the "pure rules" described on 
+	a(href="http://www.inference.org.uk/mackay/ultima/ultima.html") this page
+	| , which slightly differ from the initial rules.
+	| The aim is to get rid of the weird suicide rule, weakening the immobilizers lock
+	| (in particular, in the original rules two adjacent immobilizer are stuck forever
+	| until one is captured).
 
 h3 Capturing moves
 
-// TODO...
+p
+	| Easy case first: the king captures as usual, by moving onto an adjacent square
+	| occupied by an enemy piece. But this is the only piece following orthodox rules,
+	| and also the only one which captures by moving onto an occupied square.
+	| All other pieces capture passively: they land on a free square and captured
+	| units are determined by some characteristics of the movement.
+
+p Note: the immobilizer does not capture.
+
+h4 Pawns/Pincers
+
+p.
+	If at the end of its movement a pawn is horizontally or vertically adjacent to an
+	enemy piece, which itself is next to a friendly piece (in the same direction),
+	the "pinced" unit is removed from the board.
+
+figure.diagram-container
+	.diagram
+		| fen:7k/5ppp/2N5/2n5/3rB3/8/PPP5/K7:
+	figcaption 1.Pc2c4 captures both coordinator and long leaper.
+
+h4 Coordinators (rooks)
+
+p.
+	Imagine that rook and king are two corners of a rectangle (this works if these
+	two pieces are unaligned).
+	If at the end of a rook move an enemy piece stands in any of the two remaining
+	corners, it is captured.
+
+figure.diagram-container
+	.diagram
+		| fen:8/2b4K/2q5/3p1N1p/8/8/2R5/k7:
+	figcaption 1.Rc5 captures on c7 and h5.
+
+h4 Long leapers (knights)
+
+p.
+	A knight captures exactly as a queen in draughts game: by jumping over its enemies,
+	as many times as it can/want but always in the same direction.
+	In this respect it is less powerful than a draughts' queen:
+	on the following diagram c8 or f6 cannot be captured.
+
+figure.diagram-container
+	.diagram
+		| fen:2n2b1k/3r4/8/3p4/8/3b4/3N4/K7 w d4,d6,d8:
+	figcaption All marked squares are playable from d2.
+
+h4 Withdrawer (queen)
+
+p.
+	The queen captures by moving away from an adjacent enemy piece, in the opposite
+	direction (only the long leaper can jump).
+
+figure.diagram-container
+	.diagram
+		| fen:7k/8/8/3Qr3/8/8/8/K7 w a5,b5,c5:
+	figcaption 1.Qa5, 1.Qb5 or 1.Qc5 captures the black rook.
+
+h4 Chameleon (bishop)
+
+p The chameleon captures pieces in the way they would capture. So, it
+ul
+	li pinces pawns,
+	li withdraws from withdrawers,
+	li leaps over long leapers,
+	li coordinates coordinators.
+p ...and these captures can be combined.
+
+figure.diagram-container
+	.diagram
+		| fen:7k/8/8/m3pP2/2n5/8/B7/K7 w a5,c4,e5:
+	figcaption 1.Bd5 captures all marked pieces.
+
+p.
+	Besides, chameleon immobilizes immobilizers (but cannot capture them since they
+	do not capture).
+
+p.
+	A chameleon captures the king in the same way the king captures, which means that
+	a chameleon adjacent to a king gives check.
 
 h3 End of the game
 
-// TODO: show the situation from Wikipedia page
+p.
+	Checkmate or stalemate as in standard chess. Note however that checks are more
+	difficult to see, because of the exotic capturing rules. For example, on the
+	following diagram the white king cannot move to the marked squares because then
+	the black pawn could capture by moving next to it.
+
+figure.diagram-container
+	.diagram
+		| fen:7k/8/8/p4r/4K3/8/8/8 w e5:
+	figcaption 1.Ke5 is impossible
 
 h3 Credits