Historical Milestones

Early Shatranj variants

The historian al-Mas'ûdî (المسعودي), dead in 956, composed the Murūj aḏ-Ḏahab wa-Maʿādin al-Jawhar (مُرُوج ٱلذَّهَب وَمَعَادِن ٱلْجَوْهَر Meadows of Gold and Mines of Gems). Among other things, this text described five variants of Shatranj: Oblong Shatranj (al-Mustatîla), Complete Shatranj (at-Tâmma), Byzantine Shatranj (ar-Rûmîya), Celestial Shatranj (al-Falakîya) and Limb Shatranj (al-Jawârhîya).

Today we know very little about the latter, the Limb Shatranj, and we do not know the details, but in any case, it seems to be unrelated to what we understand today as chess, although neither is the Celestial shatranj.

• Oblong Shatranj (rectangular) Shatranj al-Mustatîla

  

  This was a Shatranj played with dice, moving a piece according to the type of piece determined by the value of the die (6=Shah, 5=Firz, 4=Elephant, 3=Horse, 2=Roc, 1=Peon) on a rectangular board consisting of 16×4 squares, which often appeared behind the board game of Nard (backgammon). We note that, indeed, chess in the Middle Ages was a game of chance and gambling.

  There were several alternative initial setup positions. In case of check, if the die did not allow the Shah to move, the player lost the turn, and the game was only lost when the Shah was captured, or all pieces except the Shah were captured.

• Complete Shatranj Shatranj at-Tâmma

  

  This Shatranj used a board of 10×10 squares, adding two pieces to each player. It is the oldest known decimal chess (on a 10×10 board). Two variants are recorded:

  1. Incorporating a piece (four, two each player) which he calls Dabbābah (war machine), which in this case had the same moves as the Shah.
  2. Incorporating a piece called Camel (four, two each player) which in this case seems to move by jumping orthogonally to the third square, complementing the diagonal movement of the Elephants. This movement is not as limiting as that of the Elephant, and allows it to reach a quarter of the squares, so that the four disjointed Camels would reach the whole board, but without being able to capture each other.

  This Shatrang at-Tâmma had some different rules from the ortodox Shatranj:

  1. The Pawn promotes to a Ferz, but if the player has not yet lost its Ferz>, the extant Ferz is seized by the opponent.
  2. If a Shah successes to reach the starting square of the opposing Shah, the player obtains an half-victory.
  3. A bare Shah is not losing. He must continue to play.

  The Dabbābah piece appears in different variants throughout history, with different movements. It is also the case that the Camel appears in different variants throughout history, but its movement is typically different from this one, while this movement is sometimes linked to the Dabbābah, leaving for the Camel a movement similar to the Horse (Knight), but more elongated (3×1 and 1×3 instead of 2×1 and 1×2).

• Round Shatranj: Shatranj Al-Muddawara

  

  Circular chess has to be understood simply as a Shatranj played on a circular board. The Arabs called it Shatranj ar-Rumiya (Byzantine chess) or Shatranj al-Muddawara (circular chess), and it consisted of 64 squares, organised in four concentric rings with 16 squares each. Only two rules need to be considered, due to the circular topology of the board:

  • There are no pawn promotion. Some pawns rotate clockwise, others counterclockwise. It seems reasonable to think that the pawns will have some mark or a distinct shape to indicate the direction of rotation.
  • Two opposing pawns of the same player, placed on the same ring, consecutive squares and opposite rotation direction, can be removed by the opponent on the next turn, without counting as a move.

  It may be noted, as a curiosity, that one player's Firz can capture the opponent's Firz, since, if the board were checkered, both Firzs would be on a square of the same colour. This is different from all other Shatranj variants, in which the players' Firzs are always positioned on squares that would be of different colours on a chequered board.

  Documents in the British Library and elsewhere suggest that circular chess was played in Persia as early as the 10th century CE, and other references are found in India, and later, in Europe. There are also references that state that the shape of the pieces was different from the usual Shatranj ones, but there is no record of the shapes; probably the pawns would have had some distinctive feature to know in which direction they moved, since there are pawns in play rotating clockwise, and others counterclockwise.

  Although Forbes and Murray mention it as a diagram appearing in a 13th century English manuscript, preserved in London in the British Library (Cotton MS Cleopatra B IX), it should be noted that the Libro del ajedrez, dados y tablas of Alfonso X of Castile, written in the 13th century, does not mention circular chess; it can be deduced that at least then it was not very relevant, neither to the Iberian peninsula, nor to the Arab scholars, who were the main source of the manuscript of Alfonso X of Castile, and of whom we do not have many references either. However, it should also be noted that there is also no reference to oblong chess, despite devoting a chapter to dice games, and another to backgammon related games, which often accompanied oblong chess on the reverse.

  Ibn al-Khatib, a poet, writer, historian, philosopher and politician from Granada who lived in the 14th century, with a family of Yemeni origin who arrived in al-Andalus in the 9th century, documents the creation of circular chess, which he claims is traced to a manuscript from the year 618 found in Istanbul, which describes a round, circular chess set called Rumi, the invention of which he attributes to Abu Ali Ibn Rashiq al-Murci (d. 694). The term Rumi comes from the word the Arabs used to designate the territories of the Roman Empire, and the circular chess is often mentioned as Shatranj ar-Rumiya (Byzantine chess) in Arabic works.

  The earliest and most valid reference is that of Al-Massudi (10th century) in his encyclopaedic work on world history Meadows of Gold and Mines of Gems, and it may be relevant that he called it Shatranj ar-Rumiya (Byzantine chess), although there is no other historical evidence linking the name to Byzantium, other than the name given by the Arabs and some much later Arabic legend.

  Interest in the game revived in the 19th century, when in 1885 George Hope Verney described it in his book Chess Eccentricities, together with variants for three and four players invented by himself. It is also mentioned in the book The sports and pastimes of the people of England (1833, Joseph Strutt. Book IV, Chapter II), referring to the 13th century English manuscript preserved in London in the British Library (Cotton MS, Cleopatra B IX).

  In 1983 the English writer Dave Reynolds set out to revive it with the current rules of chess; he built a board and presented it in a pub in Lincoln (England), where it was a hit with the local players. The modern version of circular chess was born, and in 1996 the Circular Chess Society was founded to organise a tournament as a means of spreading and popularising it.

  Modern version of circular chess

  

  Circular chess gives the Shatranj greater dynamism, providing more power to the rooks, but unfortunately, losing a little power the knights. It is not an optimal solution, and for this reason it has not stood the test of time, as the complexity of the circular chessboard does not provide sufficient improvements: it forces the creation of two fronts, but it boxes the pieces more, delimiting much more their area of influence, except for the rooks. It increases the power of the rooks, but slightly reduces that of the knight (¼), and the mobility of the bishop, making the game more unbalanced. In addition, the absence of corners makes checkmate more difficult to achieve, so that probably most games ended up with the king stripped, or in a draw, a much less artistic ending than in the traditional Shatranj.

  The modern version of the circular Shatranj is circular chess, incorporating the movement of the modern Bishop and Queen, but, unfortunately, the Bishop's movement is greatly impaired by the change from a square checkerboard to the circular version. The Queen, consequently, also has a disadvantage in its diagonal moves, but it has already been said that the orthogonal moves of the Rooks gain in power, and therefore also that of the Queen is compensated; we can think of the situation with three pieces of orthogonal move each player, in a checkerboard that has only four rows, with the diminished power of the Knight and Bishop.

  This is not to say that it is not a perfectly playable game, moreover, with the advantage that there are no great studies on openings, as in orthodox chess, allowing a pleasant game for practising chess without the considerations linked to the studied openings, and with a different approach, which is why it is practised in many clubs, particularly in England. But probably the behaviour is preferable as Shatranj rather than modern chess.

  Turning the circular chess hobby into a competition means going back to the study of openings, and then the more relaxed condition of the game is lost.

  In addition to incorporating the modern Bishop and Queen move, there are some additional rules to take into consideration in the modern version of circular chess:

  1. The initial position of the pieces changes with respect to the traditional version, so that the two kings face each other (see the difference in the circular chess picture with respect to that of the Al-Muddawara).
  2. Although the double movement of the pawns is incorporated, there is no en passant capture, nor is there castling.
  3. The rules of modern chess apply to the end of the game: a stalemate is a draw, and there is no victory if the King is left naked, with no pieces.
  4. Pawns are promoted after moving six squares from their starting position to the square immediately before the opponent's starting line. The rule of circular Shatranj that allows opposing pawns of the same player to be removed is no longer necessary, since the case cannot happen.
  5. Announcing the check is not compulsory, and it is allowed to capture the opposing king if he does not retreat from a check position, winning the game.

  The modern version incorporates the queen power: there are only four rings, and three orthogonal move pieces for each player. It can also be criticised that modern long-range diagonal moves are not clearly visualised on the circular board, and may not be obvious.

  The fondness for modern circular chess lies in the great differences, both in the openings, which are not studied, and in the endgames. The basic endgames in circular chess are: king and queen; king, rook and minor piece or king and three minor pieces against king. The endgame king and pawn against king always wins, provided that the king cannot capture the pawn before it promotes or is defended. Checkmate is more difficult to achieve, and many games that would be lost in orthodox chess because of the difference in material end in a draw.

  It should also be borne in mind that as early as 1885 George Hope Verney, in his book Chess Eccentricities, already described a modern circular chess, in a version for three players, and another for four players, the latter to be played in two pairs, and with acceptable rules for a multiplayer chess.

• Celestial Shatranj al-Falakîya Shatranj

  

  Although not much information remains, partly because it was a game intended to be guided by some erudite of the time with some knowledge of astrology, it seems that the game called Escaques detailed by Alfonso X in the Libro de los juegos: acedrex, dados e tablas of 1283 could almost be the transcription of al-Falakîya Shatranj, a game for seven players on a circular board divided into seven concentric rings, each one for one of the celestial bodies (in order: Moon, Mercury, Venus, Sun, Mars, Jupiter, Saturn), the innermost one for the Moon, and each of the rings divided into small sectors as squares. But Alfonso X also indicates that he does not leave the complete information, because it should only be available to wise men.

  The different rings did not have the same number of squares, the numbers being, in order from the inside: 12, 24, 36, 48, 60, 72 and 84. In addition, the innermost circle, inside the moon ring, is divided into four, for the four elements: fire, air, water and earth. The seven tokens, one for each celestial body, had stipulated colour and shape, for example, for the Moon, the token was to be represented by A woman dressed in white, and with her hands above her head holding the figure of the moon, Mars a classical soldier, or Venus a woman with a mirror and a comb.

  It was a gambling game very unrelated to Shatranj, despite bearing the name, but was related to playful astrological divination. Each player started with twelve points, and the game was played with a seven-sided die that determined which star had to move, and another die indicating how many moves had to be made. The resulting position of the celestial body in relation to the other celestial bodies determined, according to rules, the winnings or losses; these rules are largely determined by the astrology of Claudius Ptolemy (100 - 170 CE).

  A seven-sided die usually refers to a long die, or a teetotum, eight sided, discarding one of the values.

Scachs d'amor (1474)

The Valencian poem Scachs d'amor from 1474, by the Valencian poets Bernat Fenollar, Narcís Vinyoles and Francí de Castellví, is the oldest surviving reference to the modern rules of orthodox chess. All the rules of modern chess, including En passant captures and moves of all pieces, appear for the first time in this poem, with the Queen described for the first time with her modern moves. He also describes the same limitations on castling in modern chess, when he describes the limitations on King's Leap, a two-square jumping move that the King could make on its first move, which evolved into castling, despite the fact that both movements coexisted for a long time.

Even so, we find some rules concerning the Queen that do not apply today, perhaps the only discordant points with modern chess:

• You cannot have more than one Queen on the checkerboard (verse LVII).
• The queens cannot capture each other (verse LX).
• If the queen is lost, the game is lost (verse LXIII).

It should be noted that the rule of not allowing a player to have more than one Queen was common at the time, for ethical reasons, since it represented royal marriage. Sometimes the stratagem of calling the first piece Queen was used, reserving the name of Lady when a second piece was obtained through promotion.

We also see in the poem Scachs d'amor two other rules that are not in force today either: First, it endows the Queen with a true royal character when it is stated that if the queen is lost, the game is lost, but the royal character is now a condition reserved for the King in chess, a sexist aspect inherited directly from history.

The third case occurs when it is indicated that the queens cannot capture each other, which suggests a reminiscence of the figure of the Ferz, inherited from the Shatranj, since it was a colour bounded figure, and the initial position for the white ones were white, and for the black ones, black. Thus, before changing the movements of this piece, the Ferz, already known in Europe as Queen, could not capture the opponent's, simply because she could not move to a square of another color. The rule incorporated in Scachs d'amor seems to be nothing more than transitional, preserving a characteristic of the game of the time.

This poem, from the same date as the monarchical unification of the kingdoms of Castile and Aragon by the Catholic Monarchs, perhaps incorporates a certain influence from Isabel of Castilla as queen, despite the fact that, as has already been commented, a piece with the name de Queen had already been incorporated into European chess for almost 500 years. The point highlighted by the defenders of this thesis is that now the piece goes from being a weak piece to being the most powerful piece on the checkerboard. This fact may be merely coincidental, but, in any case, it could have contributed to the acceptance of the new piece. It must also be remembered that the poem uses the word Lady much more than the name Queen which had been adopted in France and incorporated into Latin as Regina for the medieval Ferz; Even so, the position on the checkerboard, next to the King, does not leave many more options to the imagination.

Although it does not represent a game with particularly noteworthy moves, it is the first game that has been referenced using the current rules. The full text of the poem Scachs d'amor, along with the depiction of the game, can be found at Viquitexts. The game, in interactive mode, can be found, for example, at chessgames.com.

This new style of chess started in Spain was called Queen's Chess, but it caused a lot of controversy, and in different circles of enraged male players began to call it madwoman’s chess, scacchi alla rabiosa, they also called it Scacchi de la donna in Italy, or Welsches Schachspiel (French Chess) in Germany. Thanks to the advent of the printing press and the popularity of chess books at the time, the Queen's Chess spread quickly throughout Europe, with Francesc Vicent being the first to spread the new rules of the game. The appearance of some powerful women at the beginning of the Renaissance could also have contributed to the acceptance of the great power of the Queen: Caterina Sforza (1463-1509), Isabella d'Este (1474-1539), Lucrezia Borgia (1480-1519), Caterina de Medici (1519-1589). Lucrezia Borgia welcomed Francesc Vicent, and Isabella d'Este welcomed Leonardo da Vinci and Luca Pacioli, who dedicated the chess book Schifanoia to her.

Castling, together with the promotion of pawns, would be the two latest rules of chess, since they were not fully established until mid-17th century. The peninsula was one of the last places where castling began to be used, perhaps because the rules for the King's leap were already established, known both in the poem Scachs d'amor, and in the publication by Ramirez de Lucena. These early rules prohibited the King from jumping other pieces in the move, so castling done manually in two moves was not possible.

Francesc Vicent: Llibre dels jochs partits dels schacs en nombre de 100 (1495)

The Llibre dels jochs partits dels schacs en nombre de 100 is the world's first modern chess treatise, written by Francesc Vicent, a Valencian chess player and writer. It was published in Valencia in 1495, despite the fact that no copy has reached the present day. It is known that there was a copy in the library of the Monastery of Montserrat, but it disappeared during the Napoleonic invasion.

Vincent is considered the founder of modern chess, as his work, as far as is known, spread throughout Europe the innovation of the queen, a piece that appears documented for the first time in the poem Scachs d'amor (1474). In 1506 we find another reference to Vicent in Italy, at the court of the Ferrara family. This is confirmed by the Italian master A. Sanvito, from the court of Lucrezia Borgia, when he mentions a maestro Francesco Spagnolo maestro di scachi.

Now, the Valencian researcher José A. Garzón argues that the codex of Cesena, which dates from 1502 and was found in 1995 in the Malatesta Library in Cesena (Italy), includes 100 problems from Vicent's book, and in several chess problems the original writing in Valencian by Vicent survived, with expressions from València at the end of the 15th century. There seems to be no doubt that this treatise is the origin of other texts, but, in addition, it seems that Lucena's book would be a translation into Castilian of Vicent's original written in Valencian. The dependence of the treatises by Lucena (1497) and Damiano (1512) on Vicent's work has already been pointed out. In fact, it can be observed that Damiano's work was written in the environment of Pope Alexander VI and his sons, and Vicent can be placed in 1506 at the court of Lucrezia, daughter of Alexander VI, as her chess teacher. The contents of Damiano's book could be a reprint of Vicent's modern chess materials.

Repetición de Amores et Arte de Axedrez con CL Juegos de Partido (1497)

The oldest printed rules of modern western chess that have survived to this day are found in the publication Repetición de Amores et Arte de Axedrez con CL Juegos de Partido from 1497, written by Luis Ramirez de Lucena.

It includes the modern rules of the game, but also the old ones, and shows the fundamental ideas of multiple openings and defenses. It also explains concepts such as the development of the pieces, problems of the advance of the pawns, the importance of occupying the center...

Many of the contents coincide with the Göttingen manuscript, which is why it is thought that it was one of the sources used by Luis Ramirez de Lucena.

De ludo scachorum o Schifanoia (1500)

A Latin manuscript chess treatise by Luca Pacioli, a mathematician of the early Renaissance, with Italian courts acting as patrons of artists and thinkers. De ludo scachorum, also known as Schifanoia, which would come to mean chasing tedium, includes about a hundred chess problems, some from medieval chess, but many from the new Queen's Chess. The manuscript has been discovered recently, in 2006, among a library collection of more than 26,000 volumes in the Coronini Cronberg palace in Gorizia (Italy). Its importance lies in the fact that the chess diagrams in this book were probably made by Leonardo da Vinci.

Luca Pacioli and Leonardo da Vinci were friends, and Leonardo had already illustrated the book by Pacioli De divina proportione. Both fled Milan when it was invaded by Louis XII of France, going to Mantua, where they were received at the court of Isabella d'Este.

The manuscript is dedicated to Isabella d'Este, a princess of the duchy of Ferrara and Modena, a descendant of Alfonso V the Magnanimous, who became marquise consort and regent of the duchy of Mantua. Isabella d'Este was an outstanding humanist and patron of the arts, creating a brilliant court around her. She was also a prolific writer of letters, much of which has survived, and a great lover of the game of chess. Leonardo da Vinci painted a portrait of her.

The Escorial Manuscript (1500)

Written in Castilian from the end of the 15th century, beginning of the 16th century, it contains contains a total of 89 chess problems, of very different nature, but predominantly modern chess predominating the positions of modern chess, called "de la dama", over those of the old medieval those of the old medieval chess "del viejo".

Mostly written by the same person, but there are undoubtedly additional hands that occasionally collaborated on the text: Problem number 17 is written in beautiful calligraphy coming from another person, and a third transcribes problems 37 and 38, which are curiously written in Italian.

It is also very important that the anonymous chess player presents us with endgames from his own games, with the appearance of the first endgames of bishops of different colours and queen against rook and pawn.

On the website of the Peón eléctrico in collaboration with lichess.org we can see some of the problems in the manuscript, with interactive capabilities.

Pedro Damiano (1512)

Pedro Damiano va escriure Questo libro e da imparare giocare a scachi et de li partiti, publicat a Itàlia en 1512, del que es varen fer vuit edicions en mig segle, sent l'última de 1564. És el llibre més antic que indica la posició del tauler d'escacs, amb l'escac blanc de la fila més propera a cada jugador en la dreta.

El llibre descriu les regles del joc, ofereix consells sobre estratègia, presenta una selecció de problemes d'escacs i proporciona anàlisis d'algunes obertures, tot en el context dels nous escacs de la Reina. Es pot dir que va ser escrita en l'entorn del papa Alexandre VI, considerant els editors de les dues primeres edicions en Roma.

Study of openings, defenses and endings: 16th and 17th centuries

Once the rules were established, during the 16th and 17th centuries studies were carried out on the openings, defenses and endings, similar to those that were carried out centuries before in the Islamic world for the Shatranj.

Two rules were still to be fully defined: Castling, which was not finalized until the second half of the 17th century, evolving from a movement called the king's leap, which later allowed manual castling in two movements, to evolve finally to the current castling, not without certain variations called free castling that expanded the final positions of the King and the Rook. Free castling was popular during the 17th century, and in some places lasted until the 19th century.

Another rule that was not yet fully defined, and was not fixed until the 19th century with the creation of the world championships, was the promotion of pawns.

Indian chess variant

The indian chess variant was played in India from the 17th century (Mongolian era) until the 1960s. Even today some memory remains in some places.

Notable is Indian castling, a knight move that can be performed by the king on his first move. It can also be noted that the Bishop is represented with a Camel , while the Elephant is reserved for the more powerful Rook, as Chaturaji does.

Caïssa

Caïssa is a Greek dryad revered as the muse of chess. The myth originated from a poem called Scachia Ludus written by Marco Girolamo Vida in the 16th century. She was popularized in the poem Caïssa, written in 1763 in latin by William Jones.

Mechanical Turk (1769)

The Mechanical Turk, also known as the Automaton Chess Player, or simply The Turk, was a fraudulent chess-playing machine constructed by Wolfgang von Kempele in 1770, which appeared to be able to play a strong game of chess against a human opponent.

It was first exhibited to the court of Empress Maria Theresa of Austria in 1770, and toured Europe in the 1780s; in Paris it played a game against Benjamin Franklin, who lost. The secret of its operation was well preserved, and the Turk's greatest success came after Kempele's death, when he defeated Napoleon Bonaparte in 1809. He also played with Charles Babbage in 1820.

It was eventually given to the Peale Museum in Philadelphia, but in 1854 it was destroyed in a fire. The son of the last owner later published a book in which he explained its secrets.

Study of the history of chess

Until the 19th century the legend of Sisa was one of several theories about the origin of the game, and largely accepted as true. In the 19th century the search for the true origin of the game began, and studies on the history of chess were initiated. Books were published such as Duncan Forbes' The History of Chess: From the Time of the Early Invention of the Game in India Till the Period of Its Establishment in Western and Central Europe (1860), or, at the end of the century, José Brunet y Bellet's book El ajedrez: investigaciones sobre su origen (1890), published in Barcelona.

These early works were ambitious, but they had not done any real work on the ground, and were seriously flawed. The so-called Cox-Forbes theory was initially put forward by Captain Hiram Cox, superintendent of Palongkee (India), a town named Cox's Bazaar in his honour, and later this theory was defended and expanded by Duncan Forbes. The Cox-Forbes theory, due to a very incorrect dating of Indian documents, dated the origin of chess to 3000 BC, and originated as a transformation of Chaturaji, which they called Chaturanga, confusing both games. In the case of Mr. José Brunet y Bellet, he still considered an earlier date for the game, which he dated to 4000 BC, originating in the Egypt of the pharaohs, as he confused Senet with chess.

It was necessary to wait for Harold James Ruthven Murray to publish in 1913, after translation of various manuscripts in a serious work of research: A History of Chess (1913). The theses defended by H.J.R. Murray in this book, in general, agree with the conclusions accepted today, and the great research work he carried out is acknowledged.

Classical school (Modern) (1886)

The classical stage takes up the 18th century approaches put forward by François-André Danican Philidor, who in 1749 published the book L'analyse des échecs, analysing strategy and the importance of the pawn structure in the game as a positional factor. The romantic era had not appreciated these premises very much, although they had, to a certain extent, been taken into consideration.

It was in 1873 that Wilhelm Steinitz defeated Joseph Henry Blackburne, who was an icon of romantic chess because of his open and highly tactical style of play, making Steinitz the first world champion.

Wilhelm Steinitz's style was a practical approach, away from the showiness or elegance that had been so highly valued in the romantic era, avoiding weaknesses in one's own position, in order to create and exploit these weaknesses in the opponent's position. He was the first to systematise and dogmatise some positional principles, such as the importance of the centre, the weakness of squares, the weak pawns, the importance of the bishop pair, themes such as the bad bishop, etc... Modern players prepare patiently for the game, adopting a plan, and looking for the weak points in the opponent's position.

Notable from this school is Siegbert Tarrasch, a German Jewish doctor and chess player, who helped to assimilate the teachings of Wilhelm Steinitz. In 1897 he was editor of the German chess magazine Deutsche Schachzeitung, and was especially known in his time for the book Das Schachspiel (The Game of Chess), divided into three parts (endgame, middlegame, and opening). It was his last book, but his most successful. It was originally published in 1931. A 1976 reprint of this book is available at https://archive.org.

But, without doubt, the most outstanding representative of this school is the mathematician Emanuel Lasker, world champion between 1894 and 1921, twenty-seven years one of the best players in history. It was Lasker who won the title from Steinitz.

Some examples of games and problems from the Classical school of Chess can be found in the article by Luis Fernández Siles on chess.com.

Tactical chess (1915)

Combinations, traps, and threats. Play characterized by short-term attacks, requiring calculation by the players.

Without setting big goals or striving for long-term strategic plans, you take advantage of your opponent's mistakes with tactical superiority. The game is spent manoeuvring, seeking to gain an advantage.

The great master of tactical play was Frank Marshall, US champion for 27 consecutive years, who created the Marshall Chess Club. He was known for his swindles, tactical manoeuvres to recover from a game that might seem lost, and make a draw, or even win. He wrote the book Marshall's Chess "Swindles" (1914), which listed several games where he had used this sleight of hand.

You can read more about swindles on Wikipedia.

Positional chess (1921)

Play based on strategy, on gaining and exploiting small advantages, and on analyzing the larger position, rather than calculating the more immediate tactics.

José Raúl Capablanca used a style that embodies the concept of positional chess; for example, Capablanca often took a small advantage in endgames and used it to win the game.

Capablanca won the title from Lasker in 1921, after the interruption of chess due to the First World War. He lost the title in 1927 to Aleksandr Alekhine, and never had the chance to regain it because the Russian player always refused a rematch.

Another outstanding positional player was Salo Flohr (Salomon Mikhàilovitx Flohr), a Czechoslovakian Jew and later Soviet national hero in Czechoslovakia during the 1930s. He dominated many of the chess tournaments of the pre-war years, but his patient positional style was overtaken by the sharper, more tactical methods of the young Soviet players after the Second World War.

Hypermodern school (1927)

From the concept of positional chess came hypermodernism, or the idea of controlling the centre with pieces, not just pawns. It was accepted that each position depended on certain considerations and details intrinsic to it, and therefore the generalities and precepts of the Classical School might not be so useful. The idea emerged in the 1920s, and examples of hypermodern openings include the Grünfeld, Benoni, Indian and Alekhine defences, among others.

Richard Réti revolutionised chess strategy, claiming that the classical centre, occupied by pawns, has more disadvantages than advantages, and that dominating the centre from afar, with the action of the pieces, is a more important strategic factor. In 1924 he won a resounding victory against the World Champion José Raúl Capablanca at the New York Tournament. Réti always had an artistic vision of the game, which in a way recaptured the romantic spirit.

The other great theorist of hypermodernism was Aron Nimzowitsch who sought to systematise the art of chess in order to make it an almost scientific game. He wrote the most important treatise on chess up to that time, the book My System (Mein system, in German), published between 1925 and 1927 in the form of five booklets which became the manual for a large number of modern chess players, and is even of practical value today. This book deals with the importance of the centre and the development, concepts already mentioned and studied by Morphy and Steinitz, the great fruitfulness of the open columns as a means of reaching the seventh and eighth ranks, the passed pawn, the exchange of pieces, the pinned piece or the discovered check; most of the current themes were analysed. But his main revolution was on the concept of the pawn chain, making the French defence paradigmatic, and with it the advance variant, as well as bringing to the chess world the concepts of overprotection, already mentioned by Siegbert Tarrasch, and of prophylaxis, of which Kàrpov has been the greatest exponent.

Savielly Tartakower was also involved in the spread of hypermodernism, not only as a great chess player, but also as one of the leading chess journalists of the 1920s and 1930s.

It should be noted that hypermodernity was not considered a break with previous trends, but rather an extension, unlike the opposing trends romanticism vs. modernism or also tactical vs. positional; indeed, romanticism had had a high component of tactical chess, and modernism of positional chess. Thus we find that Aleksandr Alekhin (or Alexandre Alekhine, as he wrote it) was considered both a tactical and a positional player. Even so, hypermodern players considered Siegbert Tarrasch's classical ideas too dogmatic, and some even outdated.

Some examples of games and problems from the Hypermodern school of Chess can be found in the article by Luis Fernández Siles on chess.com.

Soviet chess (1946)

After the Second World War, a generation of Soviet chess players, led by future world champion Mikhaïl Botvínnik, began to win a series of victories over international competitors that stunned the world. Soviet players dominated chess from 1948 to 2006, with the sole exception of Boby Fischer between 1972 and 1975.

This long period of Soviet domination is often referred to as the Soviet School of Chess, which was a heterogeneous set of players who together were noted for their thorough opening preparation, highly dynamic style in the treatment of middle game positions and aggressiveness. It is true that the style changes between different players, and, for example, Mikhail Tal and Tigran Petrosian had opposite styles, the former very aggressive, the latter very positional and more defensive. But today's chess cannot be understood without the radical contributions of USSR players from the 1930s to the 1970s, and many of these contributions have common features: thorough opening preparation, and dynamic, tactical appreciation is fundamental to the evaluation of positions and the choice of game plans; in short, rigorous training and study of the game, ie, considering chess as a sport, rather than an art or a science.

The Soviet Chess School is often considered only from 1948 to 1972, the time of the defeat of the Soviets by Boby Fischer.

Some examples of games and problems from the Soviet School of Chess can be found in the article by Luis Fernández Siles on chess.com.

International Chess Day

International Chess Day is commemorated every year on 19 November, the date of birth of Cuban José Raúl Capablanca Graupera.

From the year 2020 the UN has established that the International Chess Day will now be on 20 July. Strangely enough, the change comes at a time when the machine has definitively surpassed man.

Precedents

Leonardo Torres Quevedo designed El ajedrecista in 1912, a finite automaton capable of playing the rook and king endings; he was the first true wit capable of playing chess, albeit in a very limited way.

The first software capable of participating in a complete game began with the work of Claude Elwood Shannon en 1949, in 1949, who estimated the possible moves in a game of chess at 10¹²⁰, the number of moves that would have to be analyzed using brute force; we must think that the number of atoms in the entire universe is considered less than 10⁸⁰. Shannon also gave the first indications to build a software capable of playing, limiting the depth of the investigation in the minmax tree of possibilities, and determining its value by means of a heuristic function.

The 1970s ended with small personal computers that were already capable of achieving an acceptable level for an average player, but still far from master levels, not even using large computers; but the expectations of when a machine would be able to defeat a great champion were already beginning.

Deep Blue, Deeper Blue

Beginning in the 1990s, computers began to win grandmaster games, and in February 1996 the Deep Blue computer, an IBM project, shocked the world by winning a game against the then reigning world champion, Garri Kaspàrov, over despite the fact that Kasparov won the match. In May 1997, in the rematch, the enhanced supercomputer Deeper Blue defeated the champion for the first time.

In 2007, the Rybka program proved superior to any human player, and supercomputers were no longer needed; personal computers were sufficient.

Alphazero

In December 2017, Alphazero, built with the artificial intelligence created by Deep Mind, owned by Google since 2014, acquired a superhuman level after 4 hours of trial play against himself. Unlike other programs, AlphaZero is not based on human knowledge, and its understanding of the game, outside of the basic rules, comes solely from its self-learning ability guided by a Monte Carlo search (random). His massive analysis of possible plays is based on choosing the plays that may be of most interest, using the experience acquired in his previous self-learning, applying pattern recognition. This technique is much more like the way grandmasters do it: the choice among the thousands of moves that it is capable of analyzing, and the search within these moves, is independent of the heuristics that have been programmed, and the result it is better than other programs that analyze more plays.

Russian four-player chess variant with fortresses

Russian four-player chess with fortresses only adds two rows to position the pieces, reducing the size of the board, with respect to the usual four-player chess board, by 8×4=32 squares, but adds 4 fortresses with 16 squares each, i.e. 16×4=64 squares in the fortresses, which added to the additional 64 squares, gives a total of 192 squares, instead of the 128 that a four-player chess board usually has. This chess is played by two pairs of players. These fortresses also have walls to limit the entrance, to prevent access from the enemy side, and contain some additional pieces of the player: a Rook, a Knight and a Bishop, which if white corresponds to one player, will correspond black to his partner. These additional pieces are initially placed in the player's fortress, in any position, but respecting the colour of the Bishop.

One strategy cited is to castle (short), and move the King to the fortress, this being the place where he can best protect himself. The fortresses in this chess are not related to the citadels of the Shatranj, like those in Tamerlane Shatranj, and in this case are simply extensions of the board, with the exception of the presence of the walls.

The first mention by Coxe of this Russian four-player chess is quoted and dated (1784) in Chess Eccentricities, although the date Verney refers to the game is 1850, when the full rules were published, although there is still some ambiguity on some points. This variant was also briefly described by Butrimov (1821), but the full rules were not published until Petroff (1850), who recounts that his grandfather explained that Catherine the Great (1729-1796) played this chess. Details in the article Russian four-handed chess: myths and misconceptions by Georgi Markov in Board Game Studies Journal nº9 2015. Also available at http://history.chess.free.fr.

Qiguo Xiangqi

Sometimes chess games for six or even eight players have been presented. In general, these games have been forgotten as experiments without great acceptance. However, the case that stands out is the Chinese Qiguo Xiangqi (七國象棋), The Game of the Seven Kingdoms, a chess-inspired game for up to seven players, although fewer players can also play. In this game, asking for help from an opponent who is not part of one's alliance requires the player to drink a shot of liquor; and there are similar rules, to rectify a move, if an incorrect move is made, or to ask the alliance to attack. The goal of the game is to capture enemy generals, but you also earn points for captured pieces.

The game dates back to the 11th century, and was designed by the imperial minister and historian Sima Guang to commemorate the Seven Warring States (403–221 BC). Like all chess (and related games) from the Far East (China, Japan, Korea, even Vietnam), it is played using lines to move the pieces, and vertices to place them.

A player is eliminated when his General, or eleven of his pieces other than the General, are captured. A player wins when he captures 30 pieces that are not Generals, or two Generals. In the centre is positioned the Emperor (in the picture, in yellow), a neutral figure who does not move from this position, nor can he be captured.

Each player has the following pieces:

• 1 G General: Moves like a Queen.
• 1 DG Deputy-General (Chancellor): Moves like a Rook. Equivalent to the Xiangqi Chariot.
• 1 O Officer: Moves like a Bishop.
• 1 A Archer: Moves like a Queen, but only up to 4 steps.
• 1 CB Crossbowman: Moves like a Queen, but only up to 5 steps.
• 1 CA Cannon: Moves orthogonally like the Rook; captures orthogonally, but using an intermediate piece, friendly or enemy, as a screen. Same as the Xiangqi Cannon.
• 4 C Horse: moves one step orthogonally first, then continues one to three steps diagonally outward. It can't jump over other pieces.
• 2 S Swordsman (Jian): Moves one space diagonally.
• 4 B Broadswordsman (Dao): It moves one space orthogonally.
• 1 D Diplomat (intermediary): Moves like a Queen, but cannot capture, be captured, or check. It is used as a defence, or as a platform for cannon attacks.

Continuous check, stalemate and draw

A draw, or tie between the two contestants, in competition represents ½ point for each player, and occurs:

• In case of continuous check.
• When the same move is repeated three times by both players, not necessarily consecutively.
• When there are 50 moves by each player (fifty moves) without capturing any piece or moving any pawn.

In contrast, a stalemate is considered a narrow win, which in competition only awards ¾ point to the winner, with ¼ point awarded to the stalemated player.

Otras reglas

touch-move rule

a player, having the move, who deliberately touches a piece on the board must move or capture that piece if it is legal to do so.

A move cannot be rectified once the piece has been left on the board, but an invalid or illegal move must be rectified immediately.

Conditions that make a player lose a game:

He disarranges the position of the playing pieces on the board.

He does not accept to resume within a reasonable time an interrupted game.

When a watch is used and the time is exceeded.

When he fails to comply with a legal requirement of the opponent.

If he refuses to abide by the rules.

Shafran

In 1939 the Soviet geologist Isaak Grigorevich Shafran invented Shafran's hexagonal chess, registered in 1956. It was shown at the Leipzig World Chess Exhibition in 1960, but was overshadowed by the success of Gliński's Chess, and specifically for its success in the West (London).

McCooey

Between 1978 and 1979, despite the then recent creation in 1976 of the BHCF, Dave McCooey and Richard Honeycutt developed another hexagonal chess variant also using a checkerboard of 91 hexes, although McCooey claims that, at the time they designed the game, he did not know about hexagonal chess (from Gliński).

The McCooey variant, in a certain way, we could define it as one that questions the movement of the pawns established by Gliński; the capture of the pawns is now defined with a diagonal movement, much more intuitive and close to orthodox chess, at the cost of losing a large part of the pawn game.

It is also necessary to point out that it has a more compact initial arrangement of the pieces, but for this reason it loses some interesting maneuvers that exist in the Gliński chess openings, and it also incorporates two less pawns for each player, seven, instead of nine. The central pawn, on the F-column, lacks a double move, to avoid favoring White on the initial move.

The reason for the capture movement of the pawns, Gliński had studied carefully, and it is the need to achieve a pawn structure without leaving rows between them that allow an attack with pieces of orthogonal movement, the equivalent of orthodox chess, where the holes that left in pawn structures only allow diagonal access. Even so, McCooey's variant is very playable, because the power of the pieces in a 91-hex hexagonal chess quickly develops, and we soon enter the middlegame.

The more compact initial setup allows more mobility in the center, and some distance of the pawns from the opponent's, but in the quick entry into the middlegame Gliński's setup incorporates some almost positioned, chained pawns, while in the version of McCooey, in addition to having fewer pawns, loses the power that the ability to close rows using pawn structures provides. It can also be seen that the initial setup in the McCooey Variant leaves the F-pawn initial position undefended, a point that is particularly sensitive to a knight attack.

Mini Hexchess

A small chess in a regular 37 hexes checkerboard that allows a short and relaxed game, suitable as a travel pastime. It preferably uses white for the central hex (McCooey variant), and two other colors; the only bishop the players have is white (central color).

Mini Hexchess was invented by Dave McCooey, as a gift to Hans Bodlaender, as they themselves explain on the pages of Chess Variants, a website where they kept in touch.

You can try out the game by printing out the downloadable board, and the rules are also available in PDF format for downloading; check out The Corner of this website.

Hexofen

Valeriy Trubitsyn introduces Hexofen, which follows the rules of the McCooey variant for the pawn capture move. This time a third Knight and eleven Pawns are introduced in an initial layout of the pieces, so that the Pawns cover all the columns, but are at different distances from its promotion hexes.

The interest of this variant lies in the incorporation of more pawns, and their distribution over all the columns of the checkerboard, similar to how orthodox chess or Shafran's hexagonal variant does it. Trubitsyn gives importance to the ratio of pieces, which is 0.46 (42/91), in the same way as Shafran had done, but the proportion of pieces probably has to correspond to the new topology and different mobility, and as an example we can think of the situation of the bishop, which is balanced with the introduction of a third bishop, but the rest of the pieces increase the power and mobility by a factor of 150%, almost the same as the size of the checkerboard increases, up to 91 hexachecks (142%). Even so, it is true that in hexagonal chess the number and behaviour of the pawns is very questionable, and in this case the number of pawns has been tried to be balanced, but opting for the diagonal capture, which does not increase the power of the pawns to the same extent as the other pieces, nor their mobility, in addition to the drawback of the pawn structures, which has already been discussed in the description of McCooey's variant.

Trubitsyn defines a numbering of the hexes by dividing the checkerboard into three parts, and each hex is numbered depending on the part to which it belongs, using zero for the (oblique) rows that delimit the zones; thus we find that the common rows have a double denomination: A‹0,5› = C‹5,0›, A‹5,0› = E‹0,5› y E‹5,0› = C‹0,5› ; not only for the value five in this example, but for all the zero rows defined between the centre and one of the corners. This way of numbering does not introduce any advantages, although it is true that it is symmetrical for three views of the checkerboard, but not for the two positions of the players. This configuration betrays its use for a three-player game, the Diplomat, where this numbering is very useful.

Random layout variant

Trubitsyn proposes the following conditions for a random placement of Hexofen figures (in Russian), similar to the conditions of Fischer's random Chess variant:

1. A pawn line with two advanced pawns on the fourth and eighth columns, i.e. White: a32 and e23, Black: c13 and c31.
2. The Queen, being the most active figure, is always positioned in each player's corner; white: e05, black: c55.
3. The rest of the pieces are in the second, third and fourth lines, in random order.
4. The three bishops are positioned in different colours.

C'escacs

C'escacs wants to be defined as a great hexagonal chess, keeping close to the line of Hexagonal Chess (in the IHCF sense, Gliński variant). Even so, it does not follow the movement of the IHCF Hexagonal Chess Pawns (Gliński):

1. The movement of the pawns to capture is done with a diagonal move, just as in McCooey's variant.
2. C'escacs incorporates more mobility for the Pawns: they can move in the three orthogonal directions ahead.
   • The additional rule of scornful pawn capture is introduced, which allows the player some blocking of the opponent's pawns on a column.
   • This new rule seemed preferable to a Brusky-style blocking rule, which is a mere prohibition and exception to the movement rules.
3. As a grand chess variant, it allows pawns to make a double move all over the board, when it is made forward by the column. Double move is only allowed in one of the three directions of pawn movement; thus, the pawn has a total of four possible moves without capture.
   • Therefore, en passant capture occurs all over the board, when a pawn makes a double move.
4. When the movement of the pawn is made from the initial positions it allows the triple move, except in the central column and in the two initial positions of the flanks.
   • Like the double moves, the triple move is only allowed in moves along the columns.
   • The reason for limiting the triple move on the F-central column is to prevent White from taking the central hex on the first move. Note that also in the McCooey variant, double move to take the central hex is prohibited.
   • The flank pawns are already in an advanced position compared to the others, and therefore triple move from both initial flanks positions are not allowed.
5. The solution to the problem of the structure of the pawns, in C'escacs is sought with the introduction of a new piece, the Elephant.
6. The number of pawns is thirteen, with the important reinforcement of four Elephants.

But perhaps one of the most characteristic features of C'escacs is that it incorporates classic Capablanca's chess pieces, with hexagonal moves: the Chancellor with the name Dragon, and the Archbishop with the name Pegasus.

The Elephants, a great reinforcement for the weak hexagonal pawns, were inspired by the elephants (Sin or Gaja) present in Sittuyin, Burmese chess. The same movements, as expected, are found in the bishop of ASEAN-CHESS, the chess of Southeast Asia, since it unifies, in order to preserve them, Sittuyin and other chess variants from this part of the world, direct heirs of Chaturanga. We also find these moves in the Shōgi's Silver General (銀).

On this website we find information about C'escacs:

• The rules, movements and initial disposition of the pieces
  • The special gaits of the King: the king's leap and castling.
• The notation for positions and games.
• Details of the creation of the game, its evolution, and the different motivations for the movements or the names of the pieces.

Da Vasa

Helge E. da Vasa's variant dates from 1953, and was first published in Joseph Boyer's Nouveaux Jeux d'Echecs Non-orthodoxes (Paris, 1954). Helge E. da Vasa's variant considered changing the orientation of the hexes in consideration of the mobility of the pawns, and therefore uses a diamond-shaped checkerboard. This chess allows a double initial move of the pawns, and therefore en passant captures, using nine pawns, just the same number as in Hexagonal Chess (Gliński). This variant, given its orientation in horizontal rows, also allows castling.

Brusky

Yakov Brusky in 1966 introduces small changes, but fundamentally keeping the ideas of Da Vasa. In the Brusky variant:

• The board is an irregular hexagon.
• Each player has ten pawns (one more than in the Da Vasa variant), placed in the row behind the figures.
• The capture move in front of the pawn is allowed, thus advancing it to the second rank, but only for the first move of the pawn, when it has not yet moved.
  • This was actually a successful compromise between the first version of Da Vasa variant in which the pawns captured with a diagonal move to the front, and his final version of the game, in which this capturing move was eliminated.
• Introduces a rule of blocking a pawn by an opponent's pawn: a pawn is blocked if an opponent's pawn prevents one of the two moves, thus invalidating the other move.
  • This rule seems a bit artificial and forced; perhaps the C'escacs rule of capturing the scornful pawn could be adapted to the pointed orientation of the hexes, applying it instead of this Brusky rule.

Grand Hexachess

Derick Peterson Derick Peterson published the rules for Grand Hexachess in 1997, also with a clear influence of the Da Vasa variant. Now we have a checkerboard in a regular hexagon with seven hexes on each side, making a total of 127 hexes.

The big advantage is the introduction of a regular hexagon board, but it forgets all of Brusky's improvements, and does not allow the initial double movement of the pawns, now eleven per player, which are further forward, but at the same distance from the opponent's pawns as in da Vasa's variant.

New pieces are introduced: the Vizier (C'escacs Pegasus), the War Machine (C'escacs Dragon), and the Duke, which is a compound of all the moves: six orthogonal, six diagonal and twelve knight jumps (i.e. a compound of moves of the King and the Knight).

Heptagonal Qiguo Xiangqi

There are several multiplayer games derived from chess in China, Sanguo Qi (三國棋), Game of the Three Kingdoms is for three players, and uses a hexagonal board very similar to Filek, although it is a much earlier design, probably dating back to the 12th century. The symmetry of the hexagon is very appropriate for dividing the board between three players, although hexagons are not used for the squares. The alternative, joining three half-square boards, was also thought up by the Chinese in the Sanyou Qi (三友棋), Game of the Three Friends before three-player versions appeared in Europe.

But the hexagon has many more properties, and, as we have seen, hexagonal tiles can be used for three-player or even six-player chess. The geometry can also be distorted, forcing a heptagon to be filled with a tessellation of hexagons; of course, tiles will not with regular hexagons, although geometrically very close. This tessellation uses a heptagon in the centre, perfectly suitable for the Qiguo Xiangqi, which keeps the emperor in the centre.

In this way we can obtain a heptagonal board for seven players, suitable for Qiguo Xiangqi. Heptagon with a hexagonal tessellation version (by 響尾蛇的數學天地 (Sanke) which can be seen in the illustration) is played using the tessellations, the hexes, to position the pieces, as in western chess.

Diplomat

Diplomat (Valeriy Trubitsyn, 1997), is a Hexofen variant, a chess game played on a hexagonal checkerboard of 91 hexes, to make it a three-player game. The strange numbering of the board now makes sense, and seems useful. Each of the three players incorporates: King, Queen, four Rooks, three Knights, three Bishops, but only eight Pawns (Hexofen uses eleven). In total sixty pieces, twenty from each player, on a board of 91 hexes.

The initial arrangement of the three players is symmetrical using Trubitsyn's notation:

• White: K-a55, Q-a54, R-a35, R-a53, R-a42, R-a52, N-a34, N-a33, N-a32, B-a45, B-a44, B-a43. Pawns: a25, a24, a23, a22, a21, a31, a41, a51.
• Black: K-c55, Q-c54, R-c35, R-c53, R-c42, R-c52, N-c34, N-c33, N-c32, B-c45, B-c44, B-c43. Pawns: c25, c24, c23, c22, c21, c31, c41, c51.
• Color: K-e55, Q-e54, R-e35, R-e53, R-e42, R-e52, N-e34, N-e33, N-e32, B-e45, B-e44, B-e43. Pawns: e25, e24, e23, e22, e21, e31, e41, e51.

The pawns now incorporate the three orthogonal moves forward, and four capture moves in diagonal movement, two forward and two sideways. The first move of the pawns is allowed to be a double, and promotion is given in the four hexes of the two opponent's vertices: 45, 44, 55, 54; in total, eight different promotion hexes for each player.

In Diplomat the aim is to "mate" the opponent's kings, and the different possible outcomes are set out:

• 0.66 points for each player, when all three players make a draw overall.
• 1 point for the two players who make a draw, but have won in alliance against the third player.
• 0.66 points for the player who draws with the player who has mated the third player.
• 1.33 points for the player who draws after having checkmated the third player.
• 2 points when one player beats the other two players.

Once a player is defeated, the pieces remain immobile in the places where they had been, but the game also leaves open the variant where the pieces of the defeated player, except for the King, remain the property of the winning player, as does Sanguo Qi (三國棋).

There will be a problem in determining whether the first player to lose has been defeated by only one of the players or by both, both in terms of dividing the points and in terms of taking possession of his pieces if this rule is played. Diplomatic pacts are part of the game, and common strategies can be established by players passing each other papers with notes: diplomatic couriers with different degrees of alliance (duration). Perhaps these notes can be used as a test of alliance to resolve conflict casuistries when defeating the third player.

Initial position

To meet the requirements, you usually start by positioning the white pieces, first the bishops, and leave the last three places for the King and the two Rooks, e.g. Hans L. Bodlaender's proposal:

1. A die between 1 and 4 to position the black Bishop.
2. A die between 1 and 4 to position the white Bishop.
3. A die to position the Queen.
4. A die between 1 and 5 to position a Knight.
5. A die between 1 and 4 to position the other Knight.
6. In the remaining three positions, the King and the two Rooks, with the King positioned in the middle.

The squares are counted from left to right; when a number larger than the number of empty squares is rolled, the die is rolled again.

Combinations: 4 * 4 * 6 * 5 * 4 = 1920, but the two Knights are ndistinguishable, so the combinations are half, 1920 / 2 = 960.

Castling

In the same way as in classical chess, two castling moves are defined:

1. Castling to the a-file (left for white, right for black). This would be the long castling in classical chess: 0-0-0.
2. Castling to the h-file (right for white, left for black). This would be the short castling in classical chess: 0-0.

The final positions, after castling, are the same as the final positions in classical chess, regardless of the initial positions of the King and Rook. Care must be taken, because the squares crossed by the King at castling cannot be threatened.

Dragonchess

Dragonchess
Vision of the ground board.

Thanks to: Zac Dortch, CC BY-SA

Well, if we want fantasy chess, maybe because we want to make the term Fairy Chess a reality, maybe because we are fans of the well-known D&D (Dungeons & Dragons), or maybe because since Star Trek we thought it was a good idea to do this three-dimensional chess, then Dragonchess is a really interesting Fairy Chess. It is played with fantasy figures, on a three-dimensional board: heaven, earth and underworld. It is a chess game designed by Gary Gygax himself, designer of the D&D role-playing game, and the rules can be found in the Chess Variant Pages.

Star Trek

When we talk about three-dimensional chess, one quickly thinks of Star Trek chess. In reality, the importance of this variant is mainly due to its fame from its appearance in the series, and the game is simply a reproduction of what you see there (it was merely a prop). The instructions for constructing the board were published in the Star Fleet Technical Manual, and later the rules appeared. The printed rules can be purchased from Andrew Bartmess's website, where an abridged version is also available. This chess set, due to the popularity of its image, can even be found commercially.

Impossible geometry

The possibility of a three-dimensional game with computer assistance to the players was also discussed in the C'escacs design conversations, although at that time we were talking about a very complex physical board, and a mere computer assistance to the players. Perhaps assisted play may become a modality of the future.

But artificial intelligence has come a long way since these conversations where we talked about the man-machine duality, using the machine as a tool on equal terms for both players; currently, the superiority of the machine leaves little room for the human player, but games will surely be invented along these lines, even though we will probably have to forget the physical board and resign ourselves to playing virtually.

In this sense we have talked about a game on an impossible board, to play virtually: a regular icohexahedron (polygon of 26 faces) of hexagonal faces, formed by twenty-six hexagonal boards of 169 squares each: a chess with 4_394 hexes! It is an impossible polygon, as it is not possible to make a polyhedron with regular hexagons, but this only makes the game more interesting, much like incorporating more dimensions, and the number of combinations is absolutely unthinkable.