Fairy chess piece

From Wikipedia, the free encyclopedia

Some fairy pieces
	Archbishop (knight + bishop compound)
	Chancellor (knight + rook compound)
	Grasshopper (shown as an upside-down queen)
	Nightrider or unicorn (shown as an upside-down knight)

A fairy chess piece or unorthodox chess piece is a chess piece not used in conventional chess, but used in certain chess variants and some chess problems.

1 Classification of fairy chess pieces
2 Royal pieces
3 Partial list of orthodox and fairy chess pieces
4 Parlett's movement notation
5 Ralph Betza's "funny notation"
6 External links

[edit] Classification of fairy chess pieces

It is extremely difficult to classify fairy chess pieces at all, as more and more are invented by chess composers. A specialized solving program, WinChloe, recognizes more than 1200 different fairy pieces. Most (but not all) usual fairy chess pieces fall into one of three classes, although it should be noted that some are hybrid pieces (see the Chinese pieces, for example, which can move without capture as riders yet can only capture as hoppers). It is easy to create a new type of piece by simply combining the movement powers of two or more different pieces.

[edit] Leapers

A leaper is a piece that moves a fixed distance and can jump over any pieces between its departure and destination squares. A leaper's move is usually described by giving the number of squares it moves horizontally and vertically per move. For example, the knight in orthodox chess is a (2,1) leaper, meaning it moves two squares in one direction (horizontally or vertically) and one square in the other (note that it could also be described as a (1,2) leaper - there is no significance to the order of the numbers).

In shatranj, a forerunner to chess, the pieces later replaced by the bishop and queen were also leapers: the alfil was a (2,2) leaper (moving exactly two squares diagonally in any direction), and the fers a (1,1) leaper (that is, it can move one square diagonally in any direction).

Some leapers can choose between several different lengths of move - the king in orthodox chess, for example, which can move one square in any direction, could be considered a (1,1) or (1,0) leaper.

Leapers are not able to create pins, although they are often effective forking pieces. One additional advantage is that the check of a leaper can not be resolved through imposition.

[edit] Riders

A rider is a piece that can move an unlimited distance in one direction, providing there are no pieces in the way.

There are three riders in orthodox chess: the rook can move an unlimited number of (1,0) cells and is therefore a (1,0) rider; the bishop is a (1,1) rider; and the queen is a (1,1) or (1,0) rider.

The most popular fairy chess rider is the nightrider, which can make an unlimited number of knight moves (that is, 2,1 cells) in any direction (though, like other riders, it cannot change direction half-way through its move).

Sliders are a noteworthy special case of riders which can only move between geometrically contiguous cells. All of the riders in orthodox chess are examples of sliders.

The names of riders are often obtained by taking the name of a leaper which moves a similar cell-size and adding the suffix rider. For example, the zebra is a (3,2) leaper, and the zebrarider is a (3,2) rider.

Riders can create both pins and skewers.

[edit] Hoppers

A hopper is a piece which moves by jumping over another piece, which usually can be any piece of any color (this intervening piece is called a hurdle). Unless it can jump over a piece, it cannot move. There are no hoppers in orthodox chess, although in xiangqi, the cannon captures as a hopper (when not capturing, it is a rider - the so-called Chinese pieces (see below) share this characteristic).

The most popular hopper in fairy chess is the grasshopper, which moves along the same lines as an orthodox queen, except that it must hop over some other piece and land on the square immediately beyond it. Note that hoppers generally capture by taking the piece on the destination square, not by taking the hurdle (as is the case in checkers). An exception is the locust.

[edit] Royal pieces

A royal piece is one which must not be allowed to be captured. If a royal piece is threatened with capture and cannot avoid capture next move, then the game is lost (this is checkmate). In orthodox chess, each side has one royal piece, the king. In fairy chess any other orthodox piece or fairy piece may instead be designated royal, there may be more than one royal piece, or there may be no royal pieces at all (in which case the aim of the game must be something other than to deliver checkmate).

[edit] Partial list of orthodox and fairy chess pieces

Alfil: a (2,2) leaper. Found in shatranj.
Amazon: a piece combining the powers of the queen and the knight. Also called superqueen. Note, that in the variant Knightmare Chess, an amazon is a queen that moves as either a bishop or a knight.
Andernach grasshopper: a grasshopper which changes the colour of the hurdle it leaps over. Also known as a chopper. See also Andernach chess.
Archbishop: another name for the cardinal.
Berolina pawn: a piece which moves one square diagonally forward (except on its first move, when it may move two), but captures by moving one square straight forward. Compare with pawn.
Bishop: a (1,1) rider. Found in orthodox chess.
Camel: a (3,1) leaper.
Cannon: see pao.
Cardinal: a piece combining the powers of bishop and knight. Also called a princess, archbishop or janus.
Chancellor: another name for the empress.
Checker: a (1,1) locust that can make multiple captures in one turn but cannot move backward until after it has finished a turn on the far rank of the board.
Chinese pieces: a collective name for pieces derived from units found in xiangqi, the Chinese form of chess. The most common Chinese pieces are the leo, pao and vao (each of which are derived from the Chinese cannon) and the ma (derived from the horse). Those derived from the cannon are distinguished by moving as a leaper when capturing, but otherwise moving as a rider. Less frequently encountered Chinese pieces include the moa, nao and rao.
Chopper: another name for the Andernach grasshopper.
Colonel: moves as forwards and sideaways rook, the forwards moves of a knight, or a king found in Chess with different armies.
Dabbaba: a (2,0) leaper.
Elephant: A (2,2) leaper, but it cannot jump over an intervening piece, like the ma. In Chinese Chess, the elephant is restricted to its half of the board.
Empress: a piece combining the powers of the rook and knight. Also called a chancellor or marshal.
Fers: a piece which can move one square in any direction diagonally; it can be considered a (1,1) leaper. Found in shatranj.
Fu-aad: a piece which can move 3 steps in any direction, capturing on the third step.
Giraffe: a (4,1) leaper.
Grasshopper: a hopper which moves along the same lines as a queen and lands on the square immediately beyond that of the hurdle. One of the most popular fairy pieces. In diagrams, the grasshopper is usually represented by an inverted queen.
Janus: another name for the cardinal; found in Janus chess.
King: a piece which can move one square in any direction; it could be considered a (1,0) or (1,1) leaper. Found in orthodox chess, where it is royal. A non-royal piece which moves in this way is sometimes called a man.
Khohn a piece which can move one square in any direction diagonally or one square straight forward. Found in Makruk.
Knight: a (2,1) leaper. Found in orthodox chess.
Knighted piece: any piece which, in addition to its normal powers, can move like a knight. For example, an amazon is a knighted queen.
Kraken: a piece which can leap to any square on the board, including the one it is currently on (leaping to the current square has the effect of passing a move). Compare with universal leaper.
Leo: a Chinese piece which combines the powers of the pao and vao; it is therefore a piece which moves like a queen when not capturing (that is, a (1,0) or (1,1) rider), but captures by leaping over an intervening piece and taking the piece on the leo's destination square (the captured piece can be any number of squares beyond the hurdle).
Lion: a hopper which moves along the same lines as a queen and which can land on a square any distance beyond the hurdle.
Locust: any piece which captures by hopping over its victim (as in draughts).
Maharaja: a royal amazon which is the only piece on its side.
Mao: a Chinese piece which moves like a knight except that it does not leap. It first moves one square orthogonally in any direction, and then continues in the same general direction one square diagonally. The square it is on after its orthogonal move must be vacant. For example, if a white mao is on b2 and there is a white pawn on b3, the mao cannot move to a4 or c4; if the pawn is on c3, however, it can move to both those squares (because the first part of the move is orthogonal, not diagonal).
Marshal: another name for the empress.
Moa: as the mao, but the first step is diagonal and the second orthogonal, not the other way round.
Nao: a Chinese nightrider - that is, a piece which moves as a normal nightrider (that is, a (2,1) rider) when not capturing, but which captures by leaping over an intervening piece and taking the piece on the nao's destination square (the captured piece can be any number of knight-moves beyond the hurdle).

Nightrider makes any number of knight moves in the same direction.

Nightrider: A rider which moves any number of 2,1 cells (i.e., knight moves) in the same direction. A nightrider on b2 on an empty board, therefore, can move to a4, c4, d6, e8, d3, f4, h5 and d1. A pawn of the opposing colour on d6 could be captured, but the nightrider could not move any further in that direction (i.e. it couldn't move on to e8). A pawn on b3, for example, would have no effect. On diagrams, the nightrider is usually represented by an inverted knight. One of the most popular fairy pieces.
Pao: a Chinese piece which moves like a rook when not capturing (that is, a (1,0) rider), but captures by leaping over an intervening piece and taking the piece on the pao's destination square (the captured piece can be any number of squares beyond the hurdle). Found in xiangqi (in which context it is normally known in English as a cannon).
Pawn: a piece in orthodox chess that moves one square straight forward (except on its first move, when it may move two squares), but captures one square forward diagonally. Compare with Berolina pawn.
Princess: another name for the cardinal.
Queen: a (1,0) or (1,1) rider. Combines the powers of the bishop and rook. Found in orthodox chess.
Rao: a Chinese rose - that is, a piece which moves as a normal rose when not capturing, but captures by leaping over an intervening piece and taking the piece on the rao's destination square. The captured piece can be any distance beyond the hurdle.
Rook: a (1,0) rider. Found in orthodox chess.

Rose. Moves as Nightrider, but along pseudo-circular lines. (two possible paths depicted.) Of course it may move clockwise or counter-clockwise.

Rose: a piece which moves as a nightrider, except that rather than moving in a straight line, it moves along pseudo-circular ones. A rose standing on e1 on an empty board, for instance, can move to any of the squares on the large circle c2, b4, c6, e7, g6, h4 and g2; as well as c2 and a1; or d3 and b4; or d3, e5 and g6; or f3, e5, c6 and a5; or f3 and h4. As with the nightrider, an opposite-coloured piece on any one of these squares can be captured, but prevents the rose from progressing any further along that line.
Spy found in chess variant Chess Empire, the spy can move two spaces forwards or sideways, or can move like a knight one forward and then one horizontally or vice versa. It can leap over pieces and can only move two spaces; thus, it is "trapped" on its own color like a bishop.
Superqueen: another name for the Amazon.
Universal leaper: a piece which can leap to any square on the board apart from the one it is on. Compare with kraken.
Unicorn: a name usually given to a B+N piece. In Raumschach it is a triagonal rider, moves through the vertices of the cubes.
Vao: a Chinese piece which moves like a bishop when not capturing (that is, a (1,1) rider), but captures by leaping over an intervening piece and taking the piece on the vao's destination square (the captured piece can be any number of squares beyond the hurdle).

The unicorn, represented here by an up-side-down knight, moves through the vertices of cubes, triagonally. A unicorn from its starting position can only reach 30 cubes. The white unicorn's destination squares are marked with a circle, black's with an X. It is important to remember that the boards are stacked, with board E on top.

Wazir: a piece which can move one square orthogonally in any direction; it can be considered a (1,0) leaper.
Zebra: a (3,2) leaper.
Zag-Zag: a rider which can move vertically or along the NE-SW diagonal.
Zag-Zig: a rider which can move vertically or along the NW-SE diagonal.
Zig-Zag: a rider which can move horizontally or along the NE-SW diagonal.
Zig-Zig: a rider which can move horizontally or along the NW-SE diagonal.

[edit] Parlett's movement notation

Taken from David Parlett's The Oxford History of Board Games (Oxford: Oxford University Press, 1999. ISBN 0-19-212998-8). Parlett uses an expression of the form m={expression}, where m stands for "move", and the expression is composed from the following elements:

1 - a distance of one (i.e. to adjacent square)
2 - a distance of two
n - any distance in the given direction
* - orthogonally or diagonally (all eight possible directions)
+ - orthogonally (four possible directions)
> - orthogonally forwards
< - orthogonally backwards
<> - orthogonally forwards and backwards
= - orthogonally sideways (used here instead of Parlett's divide symbol.)
>= - orthogonally forwards or sideways
<= - orthogonally backwards or sideways
X - diagonally (four possible directions)
X> - diagonally forwards
X< - diagonally backwards
/ - two orthogonal moves separated by a solidus denote a hippogonal move (i.e. jumping like knights)
~ - (before a move) indicates a leaper rather than a rider. Not in Parlett.

On this basis, the traditional chess king moves (1*), queen (n*), bishop (nX), rook (n+), pawn (1>) with option of (2>) initially when not taking, or (1X>) when taking; and knight (1/2).

Here is Parlett's notation for some fairy pieces:

Alfil: 2/2
Amazon: n*, 1/2
Berolina pawn: 1> (option of 2> initially)
Bishop: nX
Camel: 1/3
Cardinal: nX, 1/2
Dabbaba: 2/0
Empress: n+, 1/2
Fers: 1X
Fu-aad: 3*
Giraffe: 1/4
King: 1*
Knight: 1/2
Kraken: n/n
Lion: ~n*
Nightrider: n(1/2) (in same direction)
Pawn : 1> with option of 2> initially when not taking, or 1X>
Rook: n+
Wazir: 1+
Zebra: 2/3

[edit] Ralph Betza's "funny notation"

Ralph Betza created a classification scheme for fairy chess pieces (including standard chess pieces) in terms of the moves of basic pieces with modifiers.

For example, the FIDE Rook, which can be described as a Wazir-rider, can be notated WW, with shorthand R. The FIDE Bishop can be notated as a Fers-rider, or FF. Finally, a FIDE pawn can be notated fmWfcF (or fcFfmW), meaning it is a piece that moves forward like a Wazir, and captures forward like a Fers (and has no other moves). This is setting aside the initial two-square move and promotion.