p.boxed
- | TODO
+ | Similar to Checkers, with prisoners stacked below capturers.
+
+figure.diagram-container
+ img.img-center(src="/variants/Emergo/match_2004_U-con.jpg")
+ figcaption.text-center.
+ [Wikipedia]
+ Game played on an orthogonal depiction of a standard 9x9 Emergo board.
+
+p
+ | Nothing disappears in this game: captured pieces become part of the
+ | capturing unit. Therefore, a piece or unit will always be understood
+ | as a combination of W white (elementary) pieces and B (elementary) black
+ | ones, with
+ br
+ | W >= 0, B >= 0 and W + B >= 1.
+
+p
+ | The 9x9 board is initially empty.
+ | Each player receives 12 stackable pieces, "in hand".
+ | At each turn, a player must pick an action among the followings:
+ ul
+ li Enter a new piece (W + B = 1) on the board.
+ li Move a unit along diagonals, by one square.
+ li Capture something.
+
+h3 Entering moves
+
+p.
+ Introducing a piece such that the opponent can take it on next turn is
+ forbidden, unless another capture is already available.
+
+p At first move, white cannot place a piece at the central point.
+
+p.
+ If the opponent already placed all his pieces in hand, then a
+ "shadow piece" enters, formed by all the remaining units available
+ (thus in this case W + B > 1).
+
+p.
+ While you have pieces in hand, none of your pieces can move on the board
+ unless they capture something.
+
+h3 Captures
+
+p.
+ Captures work exactly as in Checkers: by jumping over a diagonally adjacent
+ piece to land on a free square just behind.
+ If a capture is possible, then it must be played; in this case no piece can
+ be introduced on the board.
+ If after a capture another is possible with the same piece, it must also be
+ played — except if that implies turning at 180 degrees.
+
+figure.diagram-container
+ .diagram.diag12
+ | fen:9/9/2a@1a@4/9/4a@4/3D@5/9/5A@3/6b@2 e3:
+ .diagram.diag22
+ | fen:9/9/2a@1a@4/9/4a@4/3D@5/4ba4/9/9:
+ figcaption.
+ Before and after black captures, jumping at the marked location.
+ The next white piece must be captured too.
+
+p.
+ Captures can be described formally as follows.
+ If, as white, W1/B1 jumps over W2/B2 at square S2 to land on S1', then
+ W1/(B1+1) arrives on S1' while W2/(B2-1) stays on S2.
+ If W2 = B2 - 1 = 0, nothing remains at the captured unit location.
+ As black: exchange W and B.
+
+p.
+ In other words, each unit is a stack of friendly and enemy pieces, with
+ friendly pieces on top. After each capture, the prisoners part of the
+ stack is incremented, while the jailers quantity at the captured
+ location decreases by one.
+
+p.
+ When several capturing chains are available,
+ the player must select one of the longest (as in Checkers):
+
+figure.diagram-container
+ .diagram
+ | fen:9/9/2a@1a@4/9/2bb1a@4/3C@5/9/9/9:
+ figcaption.
+ From https://www.mindsports.nl/:
+ White's only option is to capture clockwise.
+
+p.
+ A piece can be jumped over several times, as long as it contains
+ at least one enemy unit (controling it).
+
+h3 More information
+
+p
+ | You are invited to visit the
+ a(href="https://www.mindsports.nl/index.php/arena/emergo/88-rules")
+ | authors' website
+ | . The rules are also described on
+ a(href="http://www.iggamecenter.com/info/en/emergo.html") iggamecenter
+ | , where you can play Emergo.
+
+p Inventors: Christian Freeling and Ed van Zon (1986)