In Superchess http://www.superchess.nl/indexengels.htm it occurs that certain pieces have influence on adjacent pieces:
- Freeze: an enemy piece adjacent to the Magician cannot move or capture
- Non-aggressive: an enemy piece adjacent to the Femme Fatale can move but cannot capture
- Immune: a friendly piece adjacent to the Angel cannot be captured
Multi-move and multi-capture, for example:
http://www.chess.com/forum/view/chess960-chess-variants/mighty-lion-chess
From Shogi:
https://en.wikipedia.org/wiki/Shogi
- Bring a captured piece back into the game as one's own piece
From Xiangqi:
https://en.wikipedia.org/wiki/Xiangqi
- Certain pieces that are not allowed to 'see' certain other pieces
- Specific areas on the board with specific meanings - influencing the movement of specific pieces
- A piece that captures only by jumping
Restrictions on certain pieces not being able to capture certain other pieces:
http://www.chess.com/forum/view/chess960-chess-variants/massive-new-varaint
Autonomous movement:
http://www.chess.com/forum/view/chess960-chess-variants/new-piece-suggestion-the-robot2
Defining protperties of Chess variants are:
* Game state defined by a set of pieces that can occupy a discrete location ('cell') on a playing field ('board')
* Players take turns in moving one piece from one cell to another one, and the player can freely choose which of his pieces he will move.
* The cells constitute a translation-invariant tiling of the board (i.e. the local surroundings of all cells is the same).
* There are many different piece 'types', each with their own (translation-invariant) rules for how they can move.
* Each cell can be occupied by only a single piece; pieces cannot enter cells already occupied by a piece of the same side, and when they enter a cell occupied by an opponnet piece, the latter will be 'captured' and removed from the game (replacement capture).
* One of the piece types, of which each player has a single copy, is designated 'royal', and capturing it wins the game.
There are many games that break some of these rules and are still considered Chess variants because they resemble games that satisfy all the rules very much. Even orthodox Chess breaks the move-one-piece and replacement-capture rules through castling and e.p. capture, but only in exceptional cases. Suicide Chess does not have a royal piece, but otherwise is iden
Elements that a Chess variant can or cannot have without casting doubt on its status as a Chess variant:
* Promotion: some pieces change into pieces of another type upon achieving a certain feat (reaching a certain part of the board, or making a capture).
* Board zoning: certain piece types are restricted to stay in a certain sub-set of the board.
* Piece drops: captured pieces can be put back onto the board as a move
* Piece movement can be affected by occupancy of cells other than the origin and target of the move. Usually this involves occupied intermediate cells blocking the move (sliders and lame leapers), but it can also be that some occupancy is a requirement (hoppers like the Xiangqi Cannon).
* There can be different rules for moves to occupied squares (captures) and empty squares (non-captures).
* Assymmetry: both players can have completely different armies of pieces.
As the defining characteristics are not absolute requirements, most variants only satisfy them for a large part, but do have a modest amount of exceptons to them. I already mentioned castling and e.p. captures. Other examples are:
* Pieces that can make multiple moves per turn, such as the Lion in Chu Shogi. 'Rifle captures' can be seen as a back-and-forth move of a piece.
* 'Contageous' pieces, that make their capturer promote to their own type (as in Werewolf Chess).
* Pieces whose movement rules are strongly dependent on there current neighborhood (e.g. Knight-Relay Chess, where pieces attacked by a friendly Knight can then also move as a Knight.) Pieces that paralyze or passify their neighbors also fall in this class.
* Multiple royal pieces, where you either have to capture just a single one to win (absolute royalty) or all (extinction royalty).
* Pieces that disappear themselves upon making a capture. ('Kamikaze' pieces, or 'Atomic' captures).
* Pieces whose move can have side effects other than disappearence of one or more pieces somewhere else, like displacing them. ('Catapult' or 'magnetic' pieces).
* Pieces that belong to neither or both sides (i.e. that can be moved by both players).
* Anti-royalty: a piece that must remain under attack to not lose the game.
I'm still gazing at the word 'translation-invariant'. Would that allow hexagonal cell structures? Does the river in Xiang Qi make that board translation-variant?
(State of the game might also be defined by earlier events: castling and en passant depend on what happened earlier.)
I used 'translation invariant' to indicate that usually a Chess piece moves in the same way relative to its current location wherever on the board it is located. This only can have meaning when the board has the same local environment everywhere.
Again the rules are not supposed to be absolutely satisfied, but just in 'overwhelming majority'. Pieces could have special moves on special locations (e.g. in corners), and boards could have special cells (e.g. at the poles of a sperical board) without corrupting the Chess-like feel of the game.
Hexagonal tilings are certainly translation invariant: moving it so that a given hexagon covers an adjacent one makes all the neighbors of those two cover each other too. With tri-angular cells this would be a bit more tricky, as not all cells have the same orientation, which leads to problems with definition of not totally symmetric pieces.
The Xiangqi River is not really an irregularity of the board, only in its graphical representation. The division into board zones is a mild breaking of the rules. It is true that an Advisor on e1 has four moves, and one on f2 only a single one, but the latter is a sub-set of the four, rather than a totally different set. So confinement to a zone is a very special case of location-dependent moving that does not really destroy the illusion that the piece has a fixed move.
Here are some elements in my invented variants that I have came up with myself that don't follow familiar chess elements (I'm sure some of these idea has been previously used, but nevertheless, I came up with them without the influence of other things/people.):
1 - From Magician's Deathmatch:
. - Switching out a piece to replace with piece substitute - Magician piece
2 - From Dragon's Chess II: Game of Conquest (Xiangqi variant):
. - Capturing a piece by leaping over it in order to capture another piece - Elephant piece
. - Introducing a piece after a piece "crosses the river" - Dragon piece
. - Promoting a piece when it hasn't been captured after so many turns - Dragon piece
. - Promoting a piece through adjacaent placement of demoted piece to enemy piece
3 - From Chaos's Chess:
. - A third "ghost" player that is friendly to neither players
. - A third player that can only make a move after so many "regular player" moves
. - A chaotic King that is capturable and cannot be checked
4 - From Clash of Mythic Titans:
. - A piece that can be revived when captures don't occur after n moves - Pheonix piece
. - A piece that can cause immobolize an enemy piece for one turn - Pheonix piece
I think in hexagonal chess need another pieces.
I haven't seen it anywhere yet, but transparency could be something: a piece is transparent if other pieces can jump over it or attack / give check through it - while those other pieces normally cannot do that.
Or there could be a piece that influences adjacent pieces such as to become transparent.
Events. Things happening all over the board after a specified number of moves. For example in Ice Age Chess where after every 20th moves an Ice Age occurs.
http://www.chessvariants.com/boardrules.dir/iceage.html
Perhaps draw due to the 50 moves rule can also be considered an 'event'.
Obstacles: pieces that do nothing but occupy a field and so limit other pieces' movement.
Pieces of such a size that they occupy more adjacent squares.
Both these elements are from the walles and pyramids in Superchess. A wall can be removed by its owner which counts as a single move. It can be captured if it is simultaneously attacked on all squares it occupies.
Changes of board topology, for example the board could have the property that any piece can always step/leap between particular non-adjacent squares. For example cylinder chess, but also:
https://www.chess.com/forum/view/chess960-chess-variants/the-ser-board-explained
Some variants keep the ortodox pieces and movements as they are, but instead vary on other game rules. For example kung fu chess, bughouse, crazyhouse and refusal chess.
They could actually be combined with all fairy piece variants.
I haven't seen it anywhere yet, but transparency could be something: a piece is transparent if other pieces can jump over it or attack / give check through it - while those other pieces normally cannot do that.
Or there could be a piece that influences adjacent pieces such as to become transparent.
Actually the jumping generals of Tenjiku Shogi can be considered as a form of transparency. I realized that when I was writing an engine for it. It is only a 'partial' transparency, applying only to captures. But basically the rules are such that all pieces of lower rank are transparent to pieces of higher rank, while higher and equal ranks are opaque to lower / equal ranks.
I haven't seen it anywhere yet, but transparency could be something: a piece is transparent if other pieces can jump over it or attack / give check through it - while those other pieces normally cannot do that.
Or there could be a piece that influences adjacent pieces such as to become transparent.
Actually the jumping generals of Tenjiku Shogi can be considered as a form of transparency. I realized that when I was writing an engine for it. It is only a 'partial' transparency, applying only to captures. But basically the rules are such that all pieces of lower rank are transparent to pieces of higher rank, while higher and equal ranks are opaque to lower / equal ranks.
Transparency is an interesting feature. Apart from programming if we want to play On the Board or play a game here, how to represent the transparent piece?
See the Witch in the weird piece topic, and the Siege Tower by Vickalan. Games have been played with them.
Hi Zied:
Here is an example of where the Siege Tower was discussed (like a pawn, but your own pieces can move right past it): (Bulldog chess)
There is also a game with a witch (by Evert) which makes adjacent pieces invisible. If I have time to play more, I would like to try with many pawns as "Siege Towers" (not just 2). Then all your pieces can come out very fast, but pawns are still defensive because they still block opponent pieces.
Your backwards pawns, Evert's witch, and transparent pawns, will keep us with many games to play in the future.
Changes of board topology, for example the board could have the property that any piece can always step/leap between particular non-adjacent squares. For example cylinder chess, but also:
https://www.chess.com/forum/view/chess960-chess-variants/the-ser-board-explained
Actually, Janggi (Korean chess) gives an example of precisely this, as almost all pieces get extra diagonal movement within either Palace.
I'd like to have elements of chess variants listed here.
'Element' here means a really different aspect. (So a piece moving like a knight or a bishop would only combine existing elements in standard chess.)
The below list already covers standard chess and many non-standard pieces in many variants:
A chess variant is a turn-based strategic game played
- on a board with horizontally and vertically oriented squares,
- using black and white pieces.
- The game begins with pieces in some initial position (chess 960 diviates from the standard).
Each piece has certain movement capabilities. These could include:
- Horizontal by 1 or more squares
- Vertical by 1 or more squares
- Diagonal by 1 or more squares
- Knight's move
Pieces could be limited to a certain direction, like the pawn in standard chess.
Some pieces are allowed to jump over occupied squares, most are not.
The pieces can capture enemy pieces, usually by moving to the target's square.
Usually a piece captures the same way it moves (exception: the pawn in FDE chess).
Sometimes a piece is captured on a square it just passed (example: en passant in standard chess).
Some conditions allow that a piece promotes to another piece (the pawn in standard chess when reaching the last rank).
Simultaneous movement of two pieces is sometimes allowed, like castling in standard chess.
Criteria have been defined for the result of the game. This might be mating / stalemating one particular piece (King in standard chess).
Certain conditions may lead to draw in order to prevent endless continuation of a game (example: repetition of moves and 50 moves rule in standard chess).