p.boxed
- | TODO
+ | Similar to Checkers, with prisoners stacked below capturers.
+
+p
+ | The 9x9 board is initially empty.
+ | Each player receives 12 stackable pieces, "in hand".
+ | At each turn, a player must either
+ ul
+ li.
+ Enter a new piece on the board such that the opponent cannot capture it.
+ However, if a capture is already possible before the move, then
+ the piece can be dropped anywhere.
+ White cannot place a piece in the center at move 1.
+ li Play a move on the board, along diagonals.
+
+p.
+ Simple moves are Ferz moves: one step diagonally.
+ Captures work exactly as in Checkers: by jumping over a diagonally adjacent
+ piece to land on a free square just behind.
+ However, the resulting situation is more complex. See below.
+ If a capture is possible, then it must be played; in this case no piece can
+ be introduced on the board.
+
+p TODO: diagram
+
+p.
+ Let us consider each unit as a compound entity containing W white pieces
+ and B black ones (initially W = 1 and B = 0 for white units,
+ and vice-versa for black).
+ Captures can then be described formally as follows.
+
+p.
+ As white:
+ If W1/B1 jumps over W2/B2 at square S2 to land on S1', then
+ W1/(B1+1) arrives on S1' and W2/(B2-1) remains on S2.
+ If W2 = B2 - 1 = 0, nothing remains at the captured unit location.
+ As black: exchange W and B above.
+
+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" counterpart at the captured
+ location decreases by one.
+
+p.
+ When several capturing chains are available,
+ the player has to select one of the longest (as in Checkers).
+
+p TODO: diagram (from mindsports.nl)
+
+h3 More information
+
+p
+ | See the
+ a(href="https://www.mindsports.nl/index.php/arena/emergo/88-rules")
+ | Emergo page
+ | on the author's website.
+ | Rules are also described on
+ a(href="http://www.iggamecenter.com/info/en/emergo.html") iggamecenter
+ | , where you can also play this game.
+
+p Inventors: Christian Freeling and Ed van Zon (1986)