A fairy chess piece, variant chess piece, unorthodox chess piece, or heterodox chess piece is a chess piece not used in conventional chess but incorporated into certain chess variants and some unorthodox chess problems, known as fairy chess. Compared to conventional pieces, fairy pieces vary mostly in the way they move, but they may also follow special rules for capturing, promotions, etc. Because of the distributed and uncoordinated nature of unorthodox chess development, the same piece can have different names, and different pieces can have the same name in various contexts.
Most are symbolised as inverted or rotated icons of the standard pieces in diagrams, and the meanings of these "wildcards" must be defined in each context separately. Pieces invented for use in chess variants rather than problems sometimes instead have special icons designed for them, but with some exceptions (the princess, empress, and occasionally amazon), many of these are not used beyond the individual games for which they were invented.Unicode proposal for heterodox chess pieces . Quotes: "Most fairy pieces are conventionally represented by rotating the standard chess piece symbols." (p. 1); "Unlike the standard upright symbols, which always correspond to the orthodox pieces, there is no strict one-to-one correspondence between rotated symbols and particular piece types: the number of fairy pieces in use is uncountable, and the number of possible pieces is infinite. Instead, rotated symbols are assigned to pieces as needed, and the composer has wide latitude in choosing which ones they feel are appropriate, with only a few very common ones fixed by convention..." (p. 2); "The use of distinct symbols for these pieces is more common among players of the aforementioned variants than among problem enthusiasts" (p. 6).
Background
The earliest known forms of chess date from the 7th century in Persia (chatrang) and India (chaturanga). They had different rules from the modern game. The game was passed to the Arabs, then to the Europeans, and for several centuries, it was played with those ancient rules. For example, the queen was once able to move only a single square diagonally, while the bishop could jump two squares diagonally. The change of rules occurred in Spain in the end of the 15th century when the queen and the bishop were given their modern moves. In the old Muslim manuscripts those two pieces were referred as ferz (meaning advisor) and fil (meaning elephant). The queen is still called ferz and the bishop is called slon (elephant) in Russian and Ukrainian. The bishop is still called alfil (from al fil, using the article) in Spanish. Due to the pieces' change in movement, the ferz and the alfil are considered non-standard chess pieces. As those who created modern chess did in the 15th century, chess enthusiasts may still create their own rule variations and how the pieces move. Pieces that move differently from standard rules are called "variant" or "fairy" chess pieces.
The names of fairy pieces are not standardised, and most do not have standard symbols associated with them. Most are represented in diagrams by rotated versions of the icons for normal pieces, though a few exceptions sometimes get their own icons: the equihopper and the knighted pieces (princess, empress, and amazon), and a few of the basic leapers (e.g. wazir, ferz, and alfil). The common names for the pieces are used here whenever possible, but these names sometimes differ between circles associated with chess problems and circles associated with chess variants.
Classification
Many of the simplest fairy chess pieces do not appear in the orthodox game, but they usually fall into one of three classes.Dickins, Anthony S. M. (1969) . A Guide to Fairy Chess (1971 Dover repub. of 2nd ed.). Richmond, England; New York: Q Press; Dover. ISBN 0-486-22687-5; pp. 9, 30. There are also compound pieces that combine the movement powers of two or more different pieces.
Directions are defined as orthogonal (i.e. horizontal or vertical), like a rook; diagonal, like a bishop; and hippogonal, like a knight.
Simple pieces
Step-movers
Pieces that move a single square, such as a king in standard chess, are called step-movers in the context of shogi variants, but in fairy chess they are merged into the class of leapers for generality. Pieces that make hippogonal moves but cannot bypass intervening pieces, such as the xiangqi horse, may also be considered step-movers. Pieces that move a limited number of squares diagonally or orthogonally might also be considered step movers but are generally called limited ranging piece (see below).
Leapers + Names and moves of the leapers 0 1 2 34 0Zero(0) Wazir(W) (D) Threeleaper(H) 1Wazir(W)Ferz(F) Knight(N) Camel(C) Giraffe 2Dabbaba(D)Knight(N)Alfil(A) Zebra(Z) Stag 3Threeleaper(H)Camel(C)Zebra(Z)Tripper(G) Antelope4GiraffeStagAntelopeCommuter Piece names may vary. This table uses each piece's most common name.
A leaper is a piece that moves directly to a square a fixed distance away. A leaper captures by occupying the square on which an enemy piece sits. The leaper's move cannot be blocked (unlike elephant and horse in xiangqi and janggi) – it "leaps" over any intervening pieces – so the check of a leaper cannot be parried by interposing. Leapers are not able to create pins, but are effective forking pieces.
Moves by a leaper may be described using the distance to their landing square – the number of squares orthogonally in one direction and the number of squares orthogonally at right angles. For instance, the orthodox knight is described as a (1,2)-leaper or a (2,1)-leaper.Poisson, "Catégories de pièces – Types of pieces", § "Bondisseur(m,n) – (m,n)Leaper" The table to the right shows common (but by no means standard) names for the leapers reaching up to 4 squares, together with the letter used to represent them in Betza notation, a common notation for describing fairy pieces.
In shatranj, a Persian forerunner to chess, the predecessors of the bishop and queen were leapers: the alfil is a (2,2)-leaper (moving two squares diagonally in any direction), and the ferz a (1,1)-leaper (moving one square diagonally in any direction).Poisson, "Pièces féeriques – Fairy pieces", §§ "Alfil" & "Fers" The wazir is a (0,1)-leaper (an "orthogonal" one-square leaper). The dabbaba is a (0,2)-leaper. The 'level-3' leapers are the threeleaper (0,3), camel (1,3), zebra (2,3), and tripper (3,3). The (0,4), giraffe (1,4), stag (2,4), antelope (3,4), and commuter (4,4) are level-4 leapers. Many of these basic leapers appear in Tamerlane chess.
Riders A rider, or ranging piece, is a piece that moves an unlimited distance in one direction, provided there are no pieces in the way. Each basic rider corresponds to a basic leaper, and can be thought of as repeating that leaper's move in one direction until an obstacle is reached. If the obstacle is a friendly piece, it blocks further movement; if the obstacle is an enemy piece, it may be captured, but it cannot be jumped over.
There are three riders in : the rook is a (0,1)-rider; the bishop is a (1,1)-rider; and the queen combines both patterns. Sliders are a special case of riders that can only move between geometrically contiguous cells. All of the riders in orthodox chess are examples of sliders.
Riders can create both pins and skewers. One popular fairy chess rider is the nightrider, which can make an unlimited number of knight moves in any single direction. (Most fairy-chess riders cannot change direction partway through a move, though some riders in large shogi variants can; see "bent rider" below.) A nightrider is a leaper only at the local level: it is blocked by any piece on a square one of its component knight moves would fall on. That is, if a nightrider starts on a1, it can be blocked on b3 or c2, but not on a2, b2, or b1. It can only travel from a1 to c5 (a 2,4 move) if the intervening square b3 (a 1,2 move away in the same direction) is unoccupied. The names of other riders are often obtained by compounding the name of its base leaper with "rider". For example, the is a (2,3)-rider, which can make any multiple of a (2,3) move as long as no intervening (2,3) square is occupied.
Some riders do not follow a straight path. The aanca from the historical game of Grant Acedrex is such a "bent rider": it takes its first step like a ferz and continues outward from that destination like a rook. The unicorn, from the same game, takes its first step like a knight and continues outward from that destination like a bishop. The rose, which is used in chess on a really big board, traces out a path of knight moves on an approximate regular octagon: from e1, it can go to g2, h4, g6, e7, c6, b4, c2, and back to e1. The crooked bishop or boyscout follows a zigzag: starting from f1, its path could take it to e2, f3, e4, f5, e6, f7, and e8 (or g2, f3, g4, f5, g6, f7, and g8).
A limited ranging piece moves like a rider, but only up to a specific number of steps. An example is the short rook from Chess with different armies: it moves like a rook, but only up to a distance of 4 squares. From a1, it can travel in one move to b1, c1, d1, or e1, but not f1. A rider's corresponding leaper can be thought of as a limited ranging piece with a range of 1: a wazir is a rook restricted to moving only one square at a time. The violent ox and flying dragon from dai shogi (an ancient form of Japanese chess) are a range-2 rook and a range-2 bishop respectively.
There are other possible generalisations as well; the picket from Tamerlane chess moves like a bishop, but at least two squares (thus it cannot stop on the square next to it, but it can be blocked there). These are in general called ski-pieces: the picket is a ski-bishop. A skip-rider skips over the first and then every odd cell in its path: it cannot be blocked on the squares it skips. Thus a skip-rook would be a , and a skip-bishop would be an . A slip-rider is similar, but skips over the second and then every even cell in its path.
In some shogi variants (variants of Japanese chess), there are also area moves. These are similar to limited ranging pieces in that the pieces with such moves repeat one kind of basic step up to a fixed number of times, and must stop when they capture. However, unlike other riders, they may change direction during their move, and do not have a fixed path shape like riders or bent riders do.
Hoppers
A hopper is a piece that moves by jumping over another piece (called a hurdle). The hurdle can be any single piece of any color. Unless it can jump over a piece, a hopper 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). The exceptions are locusts which are pieces that capture by hopping over its victim. They are sometimes considered a type of hopper.
An equihopper must cover the same distance beyond the hurdle as before it.
There are no hoppers in Western chess. In xiangqi (Chinese chess), the cannon captures as a hopper along rook lines (when not capturing, it is a (0,1)-rider which cannot jump, the same as a rook); in janggi (Korean chess), the cannon is a hopper along rook lines when moving or capturing, except it cannot jump another cannon, whether friendly or enemy. The grasshopper moves along the same lines as a queen, hopping over another piece and landing on the square immediately beyond it. Yang Qi includes the diagonal counterpart of the cannon, the vao, which moves as a bishop and captures as a hopper along bishop lines.
Compound pieces