User:Ruziklan/Fairy pieces

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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 (often in shortened form fairy piece) or unorthodox chess piece (or in shortened form unorthodox piece) is a chess piece not used in conventional chess, but used in certain chess variants and some chess problems. These pieces vary in movement abilities and possible additional properties.

Due to distributed and uncoordinated nature of unorthodox chess development, often the same piece is referred to by different names or the same name is used for different pieces in various contexts (chess problems, various chess variants).

Contents

[edit] Classification of fairy chess pieces

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] Classification by Move Type

[edit] Interaction type: Leaper

A (m,n)leaper is a piece that moves by a fixed vector between its start square and its arrival square. One of the coordinate of the vector 'start square - arrival square' must have an absolute value equal to m and the other one an absolute value equal to n. A leaper moves in the same way to capture or not to capture, the taken unit being on the arrival square. For instance, the knight is the (1,2)leaper. [1]

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 (moving exactly one square diagonally in any direction).[2]

Some pieces can be described as combined leapers, i.e. as pieces having moevement capabilities of multiple leapers. The king in orthodox chess is, as far as only its movement is concerned without taking into account check restrictions, example of a combination of (1,1)leaper and (1,0) leaper.

Leapers are not able to create pins, although they are often effective forking pieces. One additional property is that the check of a leaper can not be parried by interposing.

[edit] Interaction type: Rider

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.

One of 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] Capture type: Locust

Any piece which captures by hopping over its victim (as in checkers). It is sometimes considered a type of hopper.

[edit] Capture type: Hopper

A hopper is a piece which moves by jumping over another piece (called a hurdle). The hurdle can usually be any piece of any color. Unless it can jump over a piece, it cannot move. 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.

There are no hoppers in orthodox chess, although in xiangqi, the cannon captures as a hopper (when not capturing, it is a rider which can not capture - 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.

[edit] Classification by Game

Some classes of pieces come from a certain game; often these have a common set of characteristics.

[edit] Chinese pieces

Main article: Xiangqi

This is 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 mao (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.

[edit] Classification by special attributes

[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, such as capturing all of the opponent's pieces).

[edit] Xed pieces

Name Notes
Crowned pieces Any piece which, in addition to its normal powers, can move like a King.
Knighted piece Any piece which, in addition to its normal powers, can move like a knight. For example, an amazon is a knighted queen.

[edit] Notations

[edit] Parlett's movement notation

In his book The Oxford History of Board Games[3] David Parlett used a notation to describe fairy piece movements. The move is specified by an expression of the form m={expression}, where m stands for "move", and the expression is composed from the following elements:

  • Distance (numbers, n)
    • 1 - a distance of one (i.e. to adjacent square)
    • 2 - a distance of two
    • n - any distance in the given direction
  • Direction (punctuation, X)
    • * - 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
  • Grouping
    • / - two orthogonal moves separated by a solidus denote a hippogonal move (i.e. jumping like knights)

[edit] Additions to Parletts

The following can be added to Parlett's to make it more complete:

  • Conditions under which the move may occur (lowercase alphanumeric, except n)
    • (default) - May occur at any point in the game
    • i - May only be made on the initial move (eg. pawn's 2 moves forward)
    • c - May only be made on a capture (eg. pawn's diagonal capture)
    • o - May not be used for a capture (eg. pawn's forward move)
  • Move type
    • (default) - Captures by landing on the piece; blocked by intermediate pieces
    • ~ - Leaper (leaps)
    • ^ - Locust (captures by leaping; implies leaper)
  • Grouping (punctuation)
    • / - two orthogonal moves separated by a solidus denote a hippogonal move (i.e. jumping like knights); this is in Parlett's, but is repeated here for completeness
    • , (comma) - separates move options; only one of the comma-delimited options may be chosen per move
    • () - grouping operator; see nightrider
    • - - range operator
  • Other:
    • & - See text for details

The format (not including grouping) is: <conditions> <move type> <distance> <direction> <other>

On this basis, the traditional chess moves are:

  • King: 1*
  • Queen: n*
  • Bishop: nX
  • Rook: n+
  • Pawn: o1>, c1X>, oi2>
  • Knight: ~1/2

[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.[4]

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.

[edit] Partial list of orthodox and fairy chess pieces

Name Parlett Found in Notes
Alfil ~2X Shatranj
Amazon n*, ~1/2 Combines 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 Andernach chess A grasshopper which changes the colour of the hurdle it leaps over. Also known as a chopper.
Archbishop See "Cardinal"
Balloon Four Dimensional Chess A bishop-like piece used in four-dimensional chess, i.e. it changes all coordinates simultaneously while moving.
Berolina pawn o1X, c1>, io2X 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 nX Orthodox Chess
Camel ~1/3
Cannon See "pao"
Cardinal nX, ~1/2 Combines the powers of Bishop and Knight. Also called a Princess, Archbishop or Janus.
Chancellor See "Empress"
Checker cn(^2X>), o1X>
King: cn(^2X), o1X
Multiple captures in one turn, or without capturing can move forward one diagonal space, but cannot move backward until after it has finished a turn on the far rank of the board. (cf. Draughts, Checkers)
Chopper See "Andernach grasshopper"
Colonel n>, n=, 2/1> 1* Moves as forwards and sideways rook, the forwards moves of a knight, or a king found in Chess with different armies.
Dabbaba ~2X
Elephant 2X Xiangqi (Chinese) 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 n+, ~1/2 Combines the powers of the Rook and Knight. Also called a Chancellor or Marshal.
Fers 1X Shatranj Move one square in any direction diagonally.
Fu-aad 3* Move 3 steps in any direction, capturing on the third step.
Giraffe ~1/4
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 Janus chess See "Cardinal"
King 1* Orthodox Chess Move one square in any direction. Royal in orthodox chess. A non-royal piece which moves in this way is sometimes called a man.
Khohn 1X, 1> Makruk Move one square in any direction diagonally or one square straight forward.
Knight ~1/2 Orthodox Chess
Kraken ~n/n 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 on*, c^& Chinese Combines the powers of the pao and vao; it 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 ~n* A hopper which moves along the same lines as a queen and which can land on a square any distance beyond the hurdle.
Maharaja A royal amazon which is the only piece on its side.
Mao Chinese 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 See "Empress"
Moa Chinese as the mao, but the first step is diagonal and the second orthogonal, not the other way round.
Nao Chinese A Chinese nightrider - 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 n(1/2) (in same direction) 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. See diagram below.
Pao Chinese 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 1>, c1X, io2> Orthodox Chess 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 See "Cardinal"
Queen n* Orthodox Chess Combines the powers of the bishop and rook.
Quang trung rook Moves as rook but when capturing must move on square away from captured piece in the same direction.
Rao Chinese A Chinese rose - 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 n+ Orthodox Chess
Rose 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. See diagram below.
Spy 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 See "Amazon"
Universal leaper 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. See diagram below.
Vao Chinese 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).
Wazir 1+ Move one square orthogonally in any direction.
Zebra ~2/3
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.
Image:chess zhor 26.png
Image:chess zver 26.png a8 b8 c8 d8 e8 xx f8 g8 h8 Image:chess zver 26.png
a7 b7 c7 d7 e7 f7 g7 h7
a6 b6 c6 d6 xx e6 f6 g6 h6
a5 b5 c5 d5 e5 f5 g5 h5 xx
a4 xx b4 c4 xx d4 e4 f4 xx g4 h4
a3 b3 c3 d3 xx e3 f3 g3 h3
a2 b2 sl c2 d2 e2 f2 g2 h2
a1 b1 c1 d1 xx e1 f1 g1 h1
Image:chess zhor 26.png
Nightrider makes any number of knight moves in the same direction.
Image:chess_zh10_26.png
Image:chess_z10ver_26.png
a10 b10 c10 d10 e10 f10 g10 h10 i10 j10
a9 b9 c9 d9 e9 f9 g9 h9 i9 j9
a8 b8 c8 d8 e8 f8 g8 h8 i8 j8
a7 b7 c7 d7 e7 f7 g7 h7 i7 j7
a6 b6 c6 d6 e6 f6 g6 h6 i6 j6
a5 b5 c5 d5 e5 f5 g5 h5 i5 j5
a4 b4 c4 d4 e4 f4 g4 h4 i4 j4
a3 b3 c3 d3 e3 f3 g3 h3 i3 j3
a2 b2 c2 d2 e2 f2 g2 h2 i2 j2
a1 b1 c1 d1 e1 f1 g1 h1 i1 j1
Image:Chess_z10ver_26.png
Image:chess_zh10_26.png
Rose. Moves as Nightrider, but along pseudo-circular lines. (two possible paths depicted.) Of course it may move clockwise or counter-clockwise.


Ea5 Eb5 Ec5 Ed5 Ee5
Ea4 Eb4 Ec4 Ed4 Ee4
Ea3 Eb3 Ec3 Ed3 Ee3
Ea2 Eb2 Ec2 Ed2 Ee2
Ea1 Eb1 Ec1 Ed1 Ee1

E

Da5 Db5 Dc5 Dd5 De5
Da4 Db4 Dc4 Dd4 De4
Da3 Db3 Dc3 Dd3 De3
Da2 Db2 Dc2 Dd2 De2
Da1 Db1 Dc1 Dd1 De1

D

Ca5 Cb5 Cc5 Cd5 Ce5
Ca4 Cb4 Cc4 Cd4 Ce4
Ca3 Cb3 Cc3 Cd3 Ce3
Ca2 Cb2 Cc2 Cd2 Ce2
Ca1 Cb1 Cc1 Cd1 Ce1

C

Ba5 Bb5 Bc5 Bd5 Be5
Ba4 Bb4 Bc4 Bd4 Be4
Ba3 Bb3 Bc3 Bd3 Be3
Ba2 Bb2 Bc2 Bd2 Be2
Ba1 Bb1 Bc1 Bd1 Be1

B

Aa5 Ab5 Ac5 Ad5 Ae5
Aa4 Ab4 Ac4 Ad4 Ae4
Aa3 Ab3 Ac3 Ad3 Ae3
Aa2 Ab2 Ac2 Ad2 Ae2
Aa1 Ab1 Ac1 Ad1 Ae1

A

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.


[edit] Notes

  1. ^ Poisson, Catégories de pièces - Types of pieces, section Bondisseur(m,n) - (m,n)Leaper
  2. ^ Poisson, Pièces – Pieces, sections Alfil, Fers
  3. ^ Parlett, 1999
  4. ^ see Betza

[edit] References

[edit] External links