In Separate Realms Chess, the standard 8 x 8 chessboard can be
viewed as being broken into multiple sets of squares or "realms"
depending on which pieces can get to them. Pawns, for example, are
limited to a realm of six squares (seven counting the moment of
promotion) unless they make a capture. The usual FIDE Bishops, being
colorbound, are limited to realms of 32 squares. All of the pieces in
Separate Realms Chess are limited to realms of 32 squares or less,
except when they capture. Some pieces, such as Pawns and Bishops, are
limited to realms of a lot less. All pieces can also change realms by
capturing.
General Rules
The rules of Separate Realms Chess are identical to those of FIDE Chess, except where noted below. The
major difference in rules is that stalemate and three-times repetition
are not draws, but loses for the stalemated or repeating player. The
rest of the differences in rules have to do with the moves of the
pieces.
The Pieces and their Movements
All of the pieces in Separate Realms Chess have at least partly
divergent moves; that is, at least some of the time they
capture differently than move without capturing. This divergence
between their capturing and non-capturing moves leads to them changing
realm at least some of the time when they capture.
The King
The King moves and captures by taking a single step diagonally, and
can also capture (but not move without capturing) by taking a single
step orthogonally. Its funny notation is
FcW. This limits the King to the squares of one color -- a realm of
32 squares -- unless it captures. Opposing Kings start in different
realms. Castling works as usual, and will cause the Rook to change realm
when performed on the Queen-side.
The black circles/'*'s indicate where the King can both move and
capture, the red circles/'!'s indicate where it can only capture.
The Knights
Of the usual eight Knight's moves, the Separate Realms Chess Knight
may make four of them -- the narrow forward and back ones -- with or
without capturing. But the other four -- the wide forward or back
moves -- may only be made when capturing. Its funny notation is
fbNcsN. This limits the Knight to every other square on every
other rank -- a realm of 16 squares -- unless it captures. The
opposing Knights start in different realms.
The black circles/'*'s indicate where the Knight can both move and
capture, the red circles/'!'s indicate where it can only capture.
The Bishops
Bishops in Seperate Realms Chess while capturing and moving without
capturing differently, capture and move without capturing in the same
directions. The Bishop moves without capturing like an Alfil-Rider,
making repeated two square diagonal jumps until reaching the edge of
the board, an occupied square, or the player decides to stop. The
Bishop captures like a FIDE Bishop, sliding diagonally. The piece's
funny notation is mAAcB. This move limits the Bishop to 1/8 of the
board -- a realm of 8 squares -- unless it captures. All four Bishops
start in different realms.
The uppermost Bishop is demonstrating the non-capturing moves, the
lowermost the capturing moves. The green circles/'+'s indicate where
the Bishop can move without capturing, the red circles/'!'s
indicate where it can only capture.
The Rooks
Like the Bishops, the Rooks in Seperate Realms Chess while capturing
and moving without capturing differently, capture and move without
capturing in the same directions. The Rook moves without capturing
like an Dabbabah-Rider, making repeated two square orthogonal jumps
until reaching the edge of the board, an occupied square, or the
player decides to stop. The Rook captures like a FIDE Rook, sliding
orthogonally. The piece's funny notation is mDDcR. This move limits
the Rook to 1/4 of the board -- a realm of 16 squares -- unless it
captures. All four Rooks start in different realms.
The uppermost Rook is demonstrating the non-capturing moves, the
lowermost the capturing moves. The green circles/'+'s indicate where
the Rook can move without capturing, the red circles/'!'s
indicate where it can only capture.
The Queen
The Separate Realms Chess Queen moves like a combination of the
Separate Realms Chess Bishop and the Separate Realms Chess Rook. Its
funny notation is mAADDcQ. This move limits the Queen to 1/4 of the
board -- a realm of 16 squares -- unless it captures. The Queens
start in different realms.
The Pawns
Separate Realms Chess Pawns move just like regular FIDE Pawns. After
all, they already are divergent and confined to a realm of consisting of a
file minus the first and last squares.
Variant
The Pawns can be moved forward to the 3rd rank (no double-move and no
en-passant). This slows the game down and creates dynamic tension in
pawn play (allow development vs. create weakness).
Notes
This game was created in the Chess Variant Pages' comment system.
Peter Aronson posted an idea for a piece (the Separate Realms Chess
Rook), and Mike Nelson created equivalent pieces for the rest of the
array except the Pawns (which are already limited to a realm and
divergent, anyway) and the King, and created a game from it. Peter
then built a ZRF and worried out loud about drawishness, so Mike
made the King colorbound and divergent like everything else. Peter
continued to worry and suggested win by stalemate, and here the game
is! Jörg Knappen and Jared B. McComb added some useful comments too.
A game that takes the theme of colorboundness even further and which
served as a partial inspiration for this game is Ralph Betza's Colorboundmost Chess.
Some other variants built around divirgent pieces are Frank Maus's
game of Thinktank Chess,
A.J. Winkelspecht's game Divergent Chess,
Michael Howe's game Biform Chess and
Christian Freeling's game Loonybird.
An alternate way of looking at realms.
We can think of the board as having four realms:
White squares on odd ranks.
Black squares on odd ranks.
White squares on even ranks.
Black squares on even ranks.
Considering only non-capturing moves, the Queen, Rooks, and Bishops are
confined to their starting realms (in the case of the Bishops, to half of
it.) The Knight alternates between two realms with opposite colors and the
same parity (odd/even). The King alternates between two realms with the same
color and opposite parity. The Pawn (disregarding the double step)
alternates between two realms of opposite color and parity. This is an
interesting symmetry: the long range pieces are confined to a single realm,
the short range pieces alternate--with each short-range piece type having
one of the three possible alternation patterns.
With every piece able to jump the pawn line, development is fast and
furious (and more than a little dangerous). Pawn play is nothing like FIDE
chess, as a pawn can help development by standing still!
Computer Play
An implementation of Separate Realms Chess has been written for Zillions of Games. You
can download it here:
