Pawn (chess)
The pawn is the most numerous piece in the game of chess, in most circumstances the weakest. It represents infantry, or more armed peasants or pikemen; each player begins a game with eight pawns, one on each square of the rank in front of the other pieces. Individual pawns are referred to by the file. For example, one speaks of "White's f-pawn" or "Black's b-pawn". Alternatively, they can be referred to by the piece which stood on that file at the beginning of the game, e.g. "White's king bishop's pawn" or "Black's queen knight's pawn". It is common to refer to a rook's pawn, meaning any pawn on the a- or h-files, a knight's pawn, a bishop's pawn, a queen's pawn, a king's pawn, a central pawn. Unlike the other pieces, pawns cannot move backwards. A pawn moves by advancing a single square, but the first time a pawn moves, it has the option of advancing two squares. Pawns may not use the initial two-square advance to capture. Any piece in front of a pawn, friend or foe, blocks its advance. In the diagram, the pawn on c4 can move to c5.
Unlike other pieces, the pawn does not capture in the same direction. A pawn captures diagonally forward one square to the right. Another unusual rule is the en passant capture, it can occur after a pawn advances two squares using its initial two-step move option, the square passed over is attacked by an enemy pawn. The enemy pawn is entitled to capture the moved pawn "in passing" – as if it had advanced only one square; the capturing pawn moves to the square over which the moved pawn passed, the moved pawn is removed from the board. The option to capture the moved pawn en passant must be exercised on the move following the double-step pawn advance, or it is lost for the remainder of the game. En passant was added in the 15th century to compensate for the newly added two-square initial move rule. Without en passant, a pawn on its initial square could safely bypass a square controlled by an advanced enemy pawn. A pawn that advances all the way to the opposite side of the board is promoted to another piece of that player's choice: a queen, bishop, or knight of the same color.
The pawn is replaced by the new piece. Since it is uncommon for a piece other than a queen to be chosen, promotion is called "queening"; when some other piece is chosen it is known as underpromotion. The piece most selected for underpromotion is a knight, used to execute a checkmate or a fork to gain a significant net increase in material. Underpromotion is used in situations where promoting to a queen would give immediate stalemate; the choice of promotion is not limited to pieces. While this extreme would never occur in practice, in game 11 of their 1927 world championship match, José Raúl Capablanca and Alexander Alekhine each had two queens in play from move 65 through move 66. While some finer sets do include an extra queen of each color, most standard chess sets do not come with additional pieces, so the physical piece used to replace a promoted pawn on the board is one, captured; when the correct piece is not available, some substitute is used: a second queen is indicated by inverting a captured rook, or a piece is borrowed from another set.
The pawn structure, the configuration of pawns on the chessboard determines the strategic flavor of a game. While other pieces can be moved to more favorable positions if they are temporarily badly placed, a poorly positioned pawn is limited in its movement and cannot be so relocated; because pawns capture diagonally and can be blocked from moving straight forward, opposing pawns can become locked in diagonal pawn chains of two or more pawns of each color, where each player controls squares of one color. In the diagram and White have locked their d- and e-pawns. Here, White has a long-term space advantage. White will have an easier time than Black in finding good squares for his pieces with an eye to the kingside. Black, in contrast, suffers from a bad bishop on c8, prevented by the black pawns from finding a good square or helping out on the kingside. On the other hand, White's central pawns are somewhat vulnerable to attack. Black can undermine the white pawn chain with an immediate...c5 and a later...f6.
Pawns on adjacent files can support each other in defense. A pawn which has no friendly pawns in adjacent files is an isolated pawn; the square in front of an isolated pawn may become an enduring weakness. Any piece placed directly in front not only blocks the advance of that pawn, but cannot be driven away by other pawns. In the diagram, Black has an isolated pawn on d5. If all the pieces except the kings and pawns were removed, the weakness of that pawn might prove fatal to Black in the endgame. In the middlegame, Black has more freedom of movement than White, may be able to trade off the isolated pawn before an endgame ensues. A pawn which cannot be blocked or captured by enemy pawns in its advance to promotion is a passed pawn. In the diagram, White has a protected passed pawn on c5 and Black has an outside passed pawn on h5. Because
Minichess
Minichess is a family of chess variants played with regular chess pieces and standard rules, but on a smaller board. The motivation for these variants is to make the game shorter than the standard chess; the first chess-like game implemented on a computer was a 6×6 chess variant Los Alamos chess. The low memory capacity of the early days computer required reduced board size and smaller number of pieces to make the game implementable on a computer. Chess on a 3×3 board does not have any defined starting position. However, it is a solved game: the outcome of every possible position is known; the best move for each side is known as well. The game was solved independently by Aloril in 2001 and by Kirill Kryukov in 2004; the solution by Kryukov is more complete, since it allows pawns to be placed everywhere, not only on the second row as by Aloril. The longest checkmate on 3 ×; the number of legal positions is 304,545,552. In 2009 Kryukov reported solving 3×4 chess. On this board there are 167,303,246,916 legal positions and the longest checkmate takes 43 moves.
In 1981 mathematician David Silverman suggested 4×4 chess variant shown on the diagram. The first player wins in this game, so Silverman proposed a variant: Black can select a pawn, White must make a first move with this pawn. However, in this case Black wins more easily. To make the variant more playable, Silverman proposed to insert a row between pawns and use the board 4×5. In this variant pawns can do double-move. Another chess variant on a 4×5 board, was invented by Glimne in 1997. Castling is allowed in this variant. There is variant on a 4×8 board, Demi-chess, invented by Peter Krystufek in 1986. Castling is allowed in this variant. A board needs to be five squares wide to contain all kinds of chess pieces on the first row. In 1969, Martin Gardner suggested a chess variant on 5×5 board in which all chess moves, including pawn double-move, en-passant capture as well as castling can be made. AISE abandoned pawn double-move and castling; the game was played in Italy and opening theory was developed.
The statistics of the finished games is the following: White won 40% of games. Black won 28%. 32% were draws. Mehdi Mhalla and Frederic Prost weakly solved Gardner minichess in 2013 and proved the game-theoretic value to be a draw. Gardner minichess was played by AISE with suicide chess and progressive chess rules. In 1980 HP shipped the HP-41C programmable calculator; the calculator was able to play on quite a decent level. In 1989, Martin Gardner proposed another setup. In difference from Gardner minichess, black pieces are mirrored. Paul Jacobs and Marco Meirovitz suggested another starting position for 5×5 chess shown at the right. Jeff Mallett, suggested setup in which white has two knights against two black bishops. There are several chess variants on 5×6 board; the earliest published one is Petty chess, invented by B. Walker Watson in 1930. Speed chess was invented by Mr. den Oude in 1988. Elena chess was invented by Sergei Sirotkin in 1999. QuickChess was invented by Joseph Miccio in 1991. Pawn double-move and castling are not allowed in this variant, pawns can only promote to captured pieces.
The game was sold by Amerigames International and received National Parenting Publications Award in 1993. Miccio obtained an USA patent in 1993. Besides two variants similar to Speed chess and Elena Chess, the patent claimed one further variant, which have been named Chess Attack. Miccio advocated these games as educational tools for children to learn chess rules; the smaller board and less pieces would reduce the complexity of the game and allow for more quicker games. The piece setup like in Speed chess was intended to teach short side castling and setup as in Chess Attack - long side castling. Laszlo Polgar published a book in 1994 Minichess 777+1 Positions devoted to chess on 5×6 board. Besides initial setup as in QuickChess, Polgar proposed to use any other possible setup of pieces asymmetrical ones; the book contained problems and games for 5×6 chess. Polgar recommended to use is as a first book to teach children to play chess. Chess Attack, which has the same setup as Gardner minichess is sold by Norway company Yes Games AS since 2008.
In this variant, pawns can make double-moves and en-passant capture is allowed. The game was endorsed by Alexandra Kosteniuk. MinitChess, published in 2010 based on earlier 2007 and 2009 variants, is played on a Gardner board with the black pieces mirrored. In this variant there is no castling, no double pawn moves, pawn promotion only to queen, victory by king capture or when an opponent has no legal move, draw after 40 moves by each side. In addition, the bishop is replaced by a bad bishop that has the additional option of moving to any adjacent empty square on its turn, allowing it to change color; this variant is intended to be easy to write computer programs to play and harder for expert human players of standard chess, while still retaining the essential character of the game: several computer tournaments have been held. Besides Los Alamos chess, there are other chess variant
Cross Chess
Cross Chess is a chess variant invented by George R. Dekle, Sr. in 1982. The game is played on a board comprising 61 cross-shaped cells, with players each having an extra rook and pawn in addition to the standard number of chess pieces. Pieces move in the context of a gameboard with hexagonal cells, but Cross Chess has its own definition of ranks and diagonals. Cross Chess was included in World Game Review No. 10 edited by Michael Keller. The Cross Chess board geometry has the same features as hexagon-based chessboards; as with hex-based boards, three cell colors are used, but same-color cells highlight horizontal ranks on the Cross Chess board, not diagonals. The diagram shows the starting setup. Special rank and diagonal paths determine as described below. Check and stalemate are as in standard chess; however a pawn has no initial two-step option, a rook can make a one-step diagonal move. A bishop moves along diagonals – adjoining cells in straight lines 33.69 degrees from the horizontal. A rook moves vertically along files and horizontally along ranks – cells of the same color in a horizontal line.
In addition, a rook may make a one-step diagonal move. The queen moves as a bishop; the king moves one step as a queen. A player may castle either queenside. In each case the king shifts to the cell occupied by the castling rook, with the rook shifting to the cell on opposite side and adjacent to the king. Normal castling conventions apply. A knight moves in the pattern: one step on a file or rank one step diagonally outward. A knight leaps any intervening men. A pawn moves one step straight with no initial two-step option. A pawn captures one step diagonally forward. Promotion occurs at the furthest cell on a file. Hexagonal chess Also by George Dekle: Masonic Chess Triangular Chess—a variant using a hexagonal board with triangular cells Hexshogi—a shogi variant with hexagonal cells Bibliography Pritchard, D. B.. The Encyclopedia of Chess Variants. Games & Puzzles Publications. ISBN 0-9524142-0-1. Pritchard, D. B.. Beasley, John, ed; the Classified Encyclopedia of Chess Variants. John Beasley. ISBN 978-0-9555168-0-1
Three-player chess
Three-player chess is a family of chess variants specially designed for three players. Many variations of three-player chess have been devised, they use a non-standard board, for example, a hexagonal or three-sided board that connects the center cells in a special way. The three armies are differentiated by color. Three-player chess variants are the hardest to design since the imbalance created when two players gang up against one is too great for the defending player to withstand; some versions attempt to avoid this "petty diplomacy" problem by determining the victor as the player who first delivers checkmate, with the third player losing in addition to the checkmated player. Other solutions have been tried as well; some variants use a board with hexagonal cells. Three bishops per side are included, to cover all cells of the hex playing field. Pieces move as in one of the versions of hexagonal chess. Chesh: Played on a 169-cell regular hexagon board. By D. R. Hofstadter. Chexs: By Stephen P. Kennedy.
Echexs: By Jean-Louis Cazaux. HEXChess: Commercial chess variant by HEXchess Inc. Three-Way Chess: Played by three players on a hexagonal board. By Richard Harshman; some variants use a hexagonal-shaped board with quadrilateral cells. Trichess: Features a "non-aggression" rule whereby a player in inferiority is immune from capture in his home portion by a numerically superior opponent, unless the capture gives check. A pawn that reaches the back rank of an opponent is exchanged for any captured friendly piece. Played on a 96-cell board. By Chistophe Langronier. ThreeChess: Checkmate does not end the game—the first player to capture an enemy king wins. A player may not move into check. Played on a 96-cell board. By the ThreeChess Team. Chess for three: By Jacek Filek. Three-Man Chess: Pawns reaching the 5th rank gain multi-direction capability; the first player to give checkmate wins. Played on a 96-cell board. By George Dekle Sr.. Trio-Chess: Played on a 96-cell board, a center triangle splits the central files.
By Van der Laken and G. J. Buijtendorp. Three-Player Chess: Played on a 96-cell board, the patent for this game provides suggested rules whereby kings are captured, the player with the last-remaining king wins; the pieces of an eliminated player may be captured. A player may move into check; the patent describes a variant whereby the army of an eliminated player is appropriated by the capturer. By Robert Zubrin. Self's Three-Handed Chess: Played on a 144-cell board. By Hency J. Self. Waidder's Three-Handed Chess: Played on a 126-cell board. By S. Waidder; some variants have used other board shapes with quadrilateral cells. III-Color-Schach: can be used with three-colored boards. Megachess: Uses a triangular board with 130 squares. Pawns have multi-direction capability. Players manage the first-mated player's army according to one of three options; the last surviving player wins. By Mega Games/Danny McWilliams. Mad Threeparty Chess: Play starts on an empty 10×10 board with players placing their pieces including an extra king per side.
Kings are designated. By V. R. Parton. Triple Chess: Uses a chessboard unbalanced by 8×3 extensions on three sides. A player must stalemate both opponents to win, using only pieces of his color. By Philip Marinelli. Triangular cells not on the perimeter have three cells obliquely adjacent, three cells adjacent at points. A variant patented in 2008 by Russian Ilshat Tagiev uses a hexagonal board with triangular cells. Armies are set up in the corners of the hexagon. Play order is clockwise around the board. All pieces adapted to the triangular boardcell geometry. Adjacent cells of the same color form the board's "diagonals". Pawns can move in any direction on horizontal lines. Pawns do not promote. A special "Rule of Neutrality" addresses the petty diplomacy problem while maintaining the possibility of cooperation: The player whose turn it is to move, can capture an enemy man only if the third player did not capture a man of that enemy on the previous move, or if that enemy captured a man of the player.
Circular boards have three - or four-sided cells, but not quadrilateral. 3 Man Chess: Uses a circular board. Some variants incorporate fairy chess pieces in addition to standard chess pieces. Orwell Chess: Uses a cylindrical board with quadrilateral cells. Armies consist of fairy pieces gryphon, pao, etc. By Glenn E. Overby. Tri-Chess: A three-player variant using an irregular hexagon board with triangular cells. Chancellors and cardinals replace queens. By George Dekle Sr.. The introduction of a third player drastically alters the style of play when standard pieces are used. Many chess openings are useless due to third player; each player must think twice as far ahead—anticipating the moves of both opponents, with the added complexity that the next player may move to attack either opponent. If a player trades off pieces with a second player, the third player benefits. Hence, players will be more reluctant to make trades. Players avoid such trades so as to carry out other strategies; the introduction of the'ext
Tri-Chess
Tri-Chess is the name of a chess variant for three players invented by George R. Dekle, Sr. in 1986. The game is played on a board comprising 150 triangular cells; the standard chess pieces are present, minus the queens, plus the chancellor and cardinal compound fairy pieces per side. Tri-Chess was included in World Game Review No. 10 edited by Michael Keller. The illustration shows the starting setup. White moves first and play proceeds clockwise around the board; when a player is checkmated or stalemated, his king is removed from the game and his remaining men become the property of the player delivering the mate or stalemate. Pawns of appropriated armies do not change their direction of movement toward promotion; the last surviving player wins the game. A bishop moves as the bishop in the Tri-Chess two-player game. A rook moves as the rook in the Tri-Chess two-player game. A knight moves in the pattern: two steps as a bishop one step as a rook in an orthogonal direction. A knight leaps any intervening men.
The chancellor moves as a knight. The cardinal moves as a knight; the king moves as the king in the Tri-Chess two-player game. The king slides three cells whether castling "cardinal-side" or "chancellor-side". A pawn captures as a pawn in Triangular Chess. Three-player chess Also by George Dekle: Three-Man Chess Triangular Chess—a two-player variant with triangular cells Trishogi—a two-player shogi variant with triangular cells Bibliography Pritchard, D. B.. "Tri-Chess". The Encyclopedia of Chess Variants. Games & Puzzles Publications. P. 323. ISBN 0-9524142-0-1. Pritchard, D. B.. "Tri-Chess ". In Beasley, John; the Classified Encyclopedia of Chess Variants. John Beasley. P. 333. ISBN 978-0-9555168-0-1
Masonic Chess
Masonic Chess is a chess variant invented by George R. Dekle, Sr. in 1983. The game is played on a modified chessboard whereby even-numbered ranks are indented to the right—resembling masonry brickwork; the moves of the pieces are adapted to the new geometry. Masonic Chess was included in World Game Review No. 10 edited by Michael Keller. The Masonic board cells are rectangular, indentation of alternating ranks results in cants 30° from the vertical and diagonals 30° from the horizontal, the same as hexagon-based chessboards when cell vertices face the players; as with hex-based boards, three colors are used, so no two adjacent cells are the same color, gameboard diagonals are highlighted. The diagram shows the starting setup. All normal chess rules apply, including conventions for castling either kingside or queenside, a pawn's initial two-step option, en passant captures, so on, but the pieces have specially defined moves. A rook cants. A bishop moves on one step as a rook; the queen moves as a bishop.
The king moves one step as a queen. A knight moves in the pattern: one step as a rook one step as a bishop in the same direction. A knight leaps any intervening men. A pawn moves one step forward as a rook. A pawn captures one step diagonally forward. De Vasa's hexagonal chess Also by George Dekle: Masonic Shogi Cross Chess—a hexagonal variant with cross-shaped cells Bibliography Pritchard, D. B.. The Encyclopedia of Chess Variants. Games & Puzzles Publications. ISBN 0-9524142-0-1. Pritchard, D. B.. Beasley, John, ed; the Classified Encyclopedia of Chess Variants. John Beasley. ISBN 978-0-9555168-0-1
Cylinder chess
Cylinder chess is a chess variant with an unusual board. The game is played as if the board were a cylinder, with the left side of the board joined to the right side. According to Bill Wall, in 947 in a history of chess in India and Persia, the Arabic historian Ali al-Masudi described six different variants of chess, including astrological chess, circular chess and cylinder chess. Cylindrical board is used in chess problems; the game is played. When a piece goes off the right edge of the board in cylinder chess, it reappears on the left edge, it is legal to move a rook from a3 to h3 if there is a piece on b3, since the rook can move left from a3. A bishop on c1 can go to h4, by moving from c1 to a3, going up and left from a3 to h4. Moves that do not change the position, like 1. Ra3-a3, are not allowed, but sometimes they are in some problems, it is allowed to capture en passant over the board edge. For example, if White has a pawn on a5, Black on h7 and Black plays 1...h7-h5, White can capture it: 2.axh6.
Bishops are more valuable in this variant. And, unlike in standard chess, a king and rook cannot enforce checkmate against a lone king on the cylindrical board; the game is sometimes played with changed rules for castling: Castling is not allowed. Proponents of this convention argue that the purpose of castling is nullified by all files being equivalent, as they are on a cylinder. In addition to normal castling, castling with the wrong rook is allowed; when castling in this way on the kingside, the king moves from e1 to g1 and the rook on a1 moves to f1. On the queenside, the king moves to c1 and the rook on h1 moves to d1; some cylinder chess problems allow moves. At the right an example of such a problem is shown; the solution is to put Black in zugzwang by playing 1. Rh4-h4. Now, after any move by Black, White has a mate; the move 1. Rg4 doesn't work because of 1... Ka5 threatening to capture the rook on h6. In Cylinder chess, the traditional hierarchy of queen, knight/bishop, pawn, is altered, with bishops becoming stronger than knights.
The knight and rook do not gain much more power from the cylindrical board, but bishops and queens gain strength. The traditional important center squares, the common moves of pawn e4, d4, e5, d5, become vulnerable moves in Cylinder chess, due to the fact that it opens up the player's center to attacks by the bishops which have been allowed access to the side squares. Piece values according to H. G. Muller are as follows: In Horizontal Cylinder chess and last rank are connected. In Toroidal chess the board has the form of a torus. One can get a toroidal board by connecting the last ranks of the cylindrical board. On the toroidal board king and queen can't checkmate a lone king, but two rooks and a king are sufficient. See the Torus Chess link below for a toroidal variant that can be played, with an explanation of moves and strategy; the adjacent diagram shows the starting position for play on a standard board, using toroidal geometry. Cylinder Chess by George Jelliss, Variant Chess, Volume 3, Issue 22, Winter 1996–67, pages 32–33.
Cylindrical chess by Ron Porter and Cliff Lundberg. BrainKing.com Internet server for playing Cylinder chess and many other chess variants Torus Chess on a standard board by Karl Fischer at the Wayback Machine Cylinder Chess a simple program by Ed Friedlander
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