Chess

Chess is a board game between two opponents in which each one initially has 16 mobile pieces that are placed on a board divided into 64 squares or squares. In its version of competition, it is considered a sport, although currently it clearly has a social, educational, and therapeutic dimension.

It is played on a grid board of 8×8 squares (also called squares), alternated in black and white colors, which constitute the 64 possible positions of the pieces for the development of the game. At the beginning of the game each player has sixteen pieces: a king, a queen, two bishops, two knights, two rooks, and eight pawns. This is a strategy game in which the goal is to "overthrow" the opponent's king. This is done by threatening the square that the king occupies with one of his own pieces without the other player being able to protect his king by interposing a piece between his king and the piece that threatens him, move his king to a free square or capture the king. piece that is threatening it, resulting in checkmate and game over.

This game, as it is known today, arose in Europe during the XV century, as an evolution of the Persian game shatranj, which in turn arose from the older chaturanga, which was practiced in India in the 6th century. The tradition of organizing chess competitions began in the 16th century. The first official world chess championship was organized in 1886. Chess is considered by the International Olympic Committee as a sport, and international competitions are regulated by FIDE. Players compete individually in different tournaments, although there are also team competitions, one of the most important being the Chess Olympics.

History of Chess

Initial layout of the pieces of the chaturanga, precedent of current chess

The predecessor of all games in the chess family, that is, not only European chess but also xiangqi, shōgi, janggi, or makruk, presumably originated in northern India as a game for four. This primitive chess would be known as chaturanga (चतुरङ्ग in Sanskrit) in Persia and after the conquest by the Arabs it would continue to develop following the Islamic expansions.

The Arabs conquered the Sasanian empire between 632 and 651. During that time they came into contact with chess. Through them came the game, which is called shatranj only by phonetic adaptation, to its first period of great splendor. As elite chess players, al-Adli (ca. 800-870) is named, who composed the first chess manual. They are followed by ar-Razi (ca. 825-860), Mawardi (in 900), as-Suli (880-946) and al-Lajlaj (in 970). We owe important literary sources to Firdausi and al-Mas'udi. It developed through a rich collection of openings (Tabjien) and endgames (Mansuben). A key element of shatranj is problem setting and problem solving. The Arabs contributed decisively to its expansion.

The game entered Europe through various routes. One of the first contacts occurred through the Byzantine Empire, especially in Constantinople. Byzantine chess, or zatrikion, is however distinguished from shatranj. The Varangians brought the game from Constantinople (Miklagard, for them) to Russia, where from the beginning of the VIII< century started playing. Through the Arabs, chess arrived in Spain in the IX century. The oldest European text containing the rules of the game is a book from the early Middle Ages, entitled Versus de Scachis written in Latin verse by an anonymous composer from the X. It probably comes from between 900 and 950 and from northern Italy. From the twelfth century comes a collection of poems composed in Hebrew by the Sephardic philosopher Abraham ibn Ezra (1089-1164). In the 13th century a famous manuscript entitled Book of Games was composed under the patronage of King Alfonso X. i> and that deals with chess, real tables (today backgammon) and dice.

Towards the end of the fifteenth century the rules began to change decisively. The movements of the pawn, the bishop and the queen would be regulated. The pawn could now take two steps on the first move (until then only one); the bishop, at any distance (until then it only jumped two squares); and the queen, at will in any of the eight directions (previously called the ensign, advanced only one square diagonally), suddenly going from being a relatively weak figure to becoming the strongest figure on the board and endowing with great spectacular to the game.

Through these adjustments the game was completely changed, the birth of modern chess. The new game required different tactics and openings. The exercise gained speed and, at the same time, popularity. These novelties were probably introduced in Valencia between the years 1470 and 1490 and were manifested in the Valencian poem Scachs d′amor, the oldest document on modern chess. The composers and at the same time famous chess players were Francesc de Castellvi, Narcis Vinyoles and Bernat Fenollar. In the year 1495, Francesch Vicent published the first chess book with the title Libre dels Jochs Partits dels Schacs en Nombre de 100 ordenat e compost. At present there is no copy of this incunabula, although there are reasons to believe that a copy should be preserved, in fact a juicy reward is offered to whoever finds one. In 2005, the historian José Antonio Garzón (Chelva, 1966), through the study of some manuscripts that are preserved in Italy, managed to recreate the book, a fact that he captured in his book The return of Francesch Vicent: The story of the birth and expansion of modern chess.

In the year 1497, a chess book by the Spanish ecclesiastic and chess player Luis Ramírez de Lucena appeared: Repetition of Amores and the Art of Chess, with 150 game games, published in Salamanca that same year. But the Gothic calligraphy with which it is written only appears around 1500, so the authorship and dating are not clear. Contains twelve openings according to the new rules and thirty chess problems. Around 1512, the learning book by Pedro Damiano titled Questo libro e da imparare giocare a scachi et de le partite appeared in Rome. This first edition marked the beginning of modern chess. As a consequence, it seems that chess circles arose, especially in the Iberian Peninsula and in Italy. At the end of the sixteenth century, Ruy López de Segura was the best player in the world. He was defeated in 1575 in the first international tournament in history organized at the court of Philip II by the Calabrian Giovanni Leonardo da Cutro, who then also defeated the best Portuguese player, El Morro, and back in Madrid, his countryman Paolo Boi. Giulio Cesare Polerio also stands out among the best chess players of his time. These personalities founded the golden age of Italian chess, which ended in 1634 with Alessandro Salvio and the death of Gioacchino Greco.

Introduction to the game

Chess game with the pieces in their initial position next to a regulatory clock

A game of chess is played between two players; each one possesses 16 pieces, being those of a light colored player, called white, and those of his opponent of dark color, called black. The pieces move on a square chessboard of 8×8 = 64 squares or also square squares, alternating light and dark colors (32 and 32). The pieces of each player at the beginning of the game are:

Parts

Whites	Black	Description
		A king
		A lady, also popularly known as queen
		Two pins
		Two horses
		Two towers, also known as Roques
		Eight pawns

Each type of piece moves in a different way, which will determine its power and its importance in the development of the game.

Chess is not a game of chance, but a rational and strategic game, since each player will decide the movement of their pieces in each turn. The development of the game is so complex that not even the best players (or the most powerful computers available) can manage to consider all the possible combinations: although the game can only be developed on a board with only 64 squares and 32 pieces at the beginning, the number of different games that can be played exceeds the number of atoms in the universe (see: Shannon number ).

The player with white starts to play, which gives them a small but essential advantage at high levels of competition, so the color of the pieces is usually drawn before the game; and in the case of tournaments, it is sought that a player has the same number of games with the white pieces as with the black ones. Thereafter both players take turns moving one of their pieces. Each player will try to gain an advantage over his opponent, either material or positional; although the ultimate goal is to attack the king so that he cannot be defended, which is known as checkmate.

Victory can also be obtained if the opponent quits or runs out of time. In tournaments, anyone who shows unsportsmanlike conduct is also declared the loser, for example by refusing to say hello at the beginning of the game or if the mobile phone rings during the game.

Another possible result is a tie or draw, which occurs in any of the following cases:

• By common agreement
• When no player has enough pieces to checkmate
• If repeated three times the same position of the pieces on the board
• When a player, without being in check, cannot make any legal moves in his turn, which is called boards by drowning
• When after fifty consecutive moves no catch has been made or a pawn has been advanced

Game Elements

To play, you need to have the chessboard and the pieces; although two people who know the positions by heart can play (blindfolded) simply by saying the movements. In addition, the rules of the game must be known. Optionally, a chess clock can be used, which is essential in competitions.

Chess during recess at school 126 Valcheta Río Negro

A physical space is also necessary, where the players develop their games. In competition games, these are usually played within a chess club and if the capacity or capacity of the club to host a maximum number of games at the same time is exceeded, the organizers usually enable a building, through permission or negotiation with their owners, such as the open space of a covered stadium, adapting a meeting room or using school classrooms as game venues.

Game Pieces

Chess pieces, Staunton model: white king, black tower and lady, black pawn, black horse and white ivory

To differentiate one side from another, a player's pieces are of a different color, one directs the light ones, called "the white ones", and the other the dark colored ones, called "the black ones". Each player has 16 pieces (pieces) of six different types, of which each player has: eight pawns, two rooks, two knights, two bishops, one queen and one king. Each piece moves on the board in a different way:

• The King you can move in any direction (vertical, horizontal and diagonal) by moving or retroceding a single box (except in the thread, in which you move two boxes).
• La Queen or Lady You can also move in any direction (vertical, horizontal and diagonal) by moving or backwards on the board the number of boxes you want, up to touch with another piece or the edge of the board.
• The Ivory You can only move in diagonal direction, as many boxes as you want.
• La Tower You can only move in the vertical and horizontal directions, not diagonally, the desired boxes.
• The Horse, according to the official definition, you can move to the nearest box that is not found in your own row, column or diagonal, although to simplify it is said that you move forward two boxes in vertical and one in horizontal, or vice versa, making a movement of ‘L’, being the only piece that can jump over the other pieces.
• The pawn You can move one or two boxes in a vertical direction in your first move, after for the first time you can only move a box, unlike the rest of the pieces you cannot go backward and you cannot capture the opposite pieces that are in the same direction in which you move, you can only do so if you are in a diagonal box about it (except in the pawn shot at the step). A pawn has the ability to become the piece that your player wants (usually in lady) if he is able to reach the last row of the board opposite to that of his side, so a pawn can acquire enormous tactical power in certain positions where he has no opposition to "coronar" (last pawn).

The word piece can take on three meanings, depending on the context:

• It may refer to any of the 32 figures.
• You can refer only to the lady, tower, bishop, horse, and perhaps also to the king, to differentiate them from the pawns.
• It can refer only to one minor piece (living or horse).

Since White has the first move advantage, the color of the pieces is assigned to each player by drawing lots. In tournaments, an attempt is made for a player to have the same number of games with white pieces and with black pieces, either by creating a fixture, alternating colors in each round, or playing an even number of rounds..

The standard pattern of pieces used in competitions is called the Staunton pattern (seen in the adjacent image), designed in 1849 by Nathaniel Cook, and named after the English champion of 19th century Howard Staunton.

The chessboard

Chess board without pieces with names of its rows and columns.

The chessboard is a square subdivided into 64 squares or equal squares (8×8), also square, alternately light and dark in color. Each player faces the opposing chess player, placing the board in such a way that each player has a white square in his right corner.

The basic elements of the board are:

• Fila. It is each of the eight lines of eight squares that form by aligning these horizontally with the players. They are named with numbers from 1 to 8, starting from the front row with respect to the side of the white pieces.
• Column. It is each of the eight eight lines of eight boxes that form by aligning these vertically with the players. They are named with tiny letters of the a until h, starting from the first left column with respect to the side of the white pieces.
• Diagonal. It is each of the 16 lines that form by grouping the boxes diagonally. The two major diagonals have eight boxes.
• Centre. The center of the board is the four central scales. By extension, sometimes the 12 around those four are included.
• Machines. Each of the four boxes located in the corners of the board.
• Bordes. The two columns (a and h) and two rows (1 and 8) located at the ends of the board.

A board can have the numbers and letters to identify the rows, columns and cells, in order to record the development of the games using algebraic notation, which is the official notation. It is frequent in the world of chess to use this system to be able to reproduce and comment on the games. It should, however, be noted that many authors and specialists have used or prefer to continue using the so-called descriptive notation.

The chessboard is also used to play checkers (when used for this game, the board is called a checkerboard).

The chess clock

Analog chess watch manufactured in the Soviet Union

Digital chess watch

The chess clock consists of a double stopwatch that measures the time each player has to make their moves. While the player's turn clock is running, his opponent's clock remains stopped, until the former makes his move and stops his clock, thus starting the opponent's clock.

Analog chess clocks are based on a mechanical operation since in order for them to work, there is a nut on the back, which must move in one direction until it cannot move anymore, called “winding up the clock”. ” and that serves to make the clock work for a time greater than that of a game. Before starting a game with this type of watch, players make sure to wind the watch, so that it is at its maximum operational capacity and does not stop in the middle of a game. These analog clocks have an element called "flag", which is held by the minute hand during the last three minutes of the time assigned to each player. When that time is exceeded, the minute hand drops the flag, and the first player whose flag falls loses the game if he has not completed the set moves or exceeds the time limit.

Currently, the most widely used are digital chess clocks based on electronic operation, using batteries, which allow different game rhythms to be set, such as the Fischer system (increment of several seconds for each move) or the Bronstein system (same as the Fischer system but without exceeding the initial time allotted); as well as determine exactly which player runs out of time first.

Game Rhythms

Time controls in chess arise from the need to avoid players taking too long to reflect on their moves, something very common until the end of the century XIX. In friendly games, the pace of play is normally agreed upon by the players, who can decide whether or not to use a clock. On the other hand, in official tournaments the time available for each player depends on the type of tournament (normal, semi-rapid, active chess, etc.) and is established by the tournament organization. A player can have a certain time for the whole game, or to reach a set number of moves; In addition, he may or may not receive a certain bonus in time for each play made. If a player runs out of time or is unable to make the allotted number of moves, he loses the game.

According to the duration of each game, this can be:

• Output Blitz or lightning: that in which each player has a maximum of 15 minutes for the whole game, or all those games with an increase of time per move in which of the sum of the increase multiplied by 60 and the initial time of reflection is not obtained a greater amount of 15 minutes.

• Quick start: that in which the time for each player is between 15 and 60 minutes, or if played with increase, that whose initial reflection time, plus the sum of the increase multiplied by 60, is included in that interval. Normally this game rhythm is used in tournament performances played with normal rhythm, and its time is set in 25 minutes.

• Standard part (classical rhythm): that in which the time of reflection per player is greater than 60 minutes. This is the most used game rate at the master level. In tournaments with a lot of participants, there is usually a control of 90 minutes per player plus 30 seconds increase per move, while elite tournaments assign time controls for a number of plays, plus a time for the end of the game. They are also called normal or slow pace games.

Games without a clock do not have a specific name, although in Spain they are popularly called friendly games or also coffee games. The name of friendly games is in contrast to the fact that it is not a competition game, therefore the result cannot affect the Elo nor create a dispute for some type of classification or prize, nor create rivalry due to this. The name of coffee games is due to the custom of playing this type of games, which are not competitive, at the tables of a bar-café, generally in a cultural center.

Summary of the rules of the game

Initial position of the pieces.

Template with the movements of the chess pieces

When the game starts, one player controls 16 white pieces and another player controls 16 black pieces. The color assigned to each player is usually raffled, although in the case of tournaments it depends on the pairing of the players. The board is placed in such a way that both players have a white square on the respective right corner square. The pieces are placed as shown in the adjacent diagram. The rooks, knights and bishops closest to the king are usually called king's (example: king's rook) and the furthest away, closest to the queen are called queen's (example: queen's bishop). Likewise, the side where the two kings originally meet is usually called kingside and the other queenside.

In traditional chess, the pieces are always placed as described. There are variants (rare in practice) in which the position of the pieces on the first row can vary (Fischer's Random Chess or Chess 960).

Players move in turns. Each turn, a player can only move one piece (with the sole exception of a special move called castling, in which the king moves two squares to the right or left and the rook moves to its opposite side). The player who plays with the white pieces is always the one who moves first.

Each type of piece moves in a different way, although the common rules for the movement of the pieces are: (see more in Chess Rules: Movement of the pieces).

• The pieces cannot jump, in their motion, one above the other (with the exception of the horse, which can jump over others, moving in ‘L’, and the tower, in the hoop).
• One piece cannot occupy a square occupied by another piece of the same color, but one occupied by another on the contrary, removing it from the board. This action is known as “take” or “capture”, and is voluntary, by the player’s decision.
• The boxes to which one piece can move, are said to be controlled for this one. If a piece is inside the boxes controlled by a piece of opposite color, it is found attacked That one.
• The king is the only piece that cannot move or pass through boxes controlled by opposite pieces.

A move that attacks the king is known as check; it is obligatory for the player whose king is under attack to get out of check. If there is no possible defense against a check, the king is checkmated. That is the objective and whoever inflicts it on the rival king wins.

A game of chess also ends when a player decides to surrender or give up, or if he exceeds the allotted time; in both cases the opponent wins the game. The game also ends when victory is not possible for any of the players, or if both agree to this result, known as a draw or draw. Likewise, the game ends in a draw if the same position on the board is repeated three times (by repetition of moves), when none of the players has enough pieces to checkmate, or if the player whose turn it is cannot make any move. regulation, a situation known as drowning.

In tournaments, and for the purpose of computing the results, the winner of a game is awarded one point, half a point to each player who has made a draw, and zero points to the loser of a game. In some tournaments 3 points are applied to the winner; one point for each player if there is a draw and zero points for the loser of a game.

Summary of chess notation rules

There are various notation systems for chess games, the purpose of which is to record games for documentary purposes. The algebraic system is the one used and recommended by FIDE. There are also other methods, such as descriptive notation (currently in disuse), or the Forsyth-Edwards system for noting particular positions.

Name for each box according to algebraic notation. The white king is placed in the e1 box at the beginning of the game.

The general rules of algebraic notation are:

• The rows of the board are named with the numbers 1 Al 8. At the beginning of the game, white pieces will occupy rows 1 and 2 and black pieces rows 7 and 8.
• The columns of the board are named with the tiny letters of the ‘a’ until ‘h’, starting with the player's left with white pieces.
• The boxes receive the name of the column and the corresponding row (e8, d5, c6, etc.).
• The pieces are designed by their initial, except the pawn: R (Rey), D (Dama), T (Torre), A (Alfil), C (Caballo).
• A move is written combining the initial of the piece and the box to which it moves, except for the pawn, of which the box is mentioned only. Examples:
  • Ce4 means a horse moves the box e4.
  • d5 represents the play of a column pawn d to fifth row.
• A catch is indicated with a x between the initial of the piece (or the column of the pawn) and the box of the captured piece. Examples:
  • Txb5 indicates that a tower captures one piece in b5.
  • dxe6 indicates that the column pawn d capture e6.
• If two equal pieces can go to the same box, the column of the moving piece is indicated; if both pieces are in the same column, the row is indicated. Examples:
  • Ced5 means that, between two horses on the same side, the one located in the column e move to the d5 box.
  • T3f6 means that, from two towers on the same side and located in the same column, the one located in the third row moves to the square f6.
• The check is indicated with a ‘+’ sign, and the checkmate with ‘++’ (or also ‘#’).
• The short enroque is scored as 0-0 and the long enroque is scored as 0-0-0.
• A step-by-step capture is indicated with: a.p.

Some symbols used to comment games are:

• !: Good play
• !: Bright play (very good)
• ?: Bad play
• ?: Very bad play
• !: Interesting play
• !: Dudosa
• ±: White window
• +/= or ±: Light white advantage
• +–: White winning window
• –/+ or (symbol ± inverted): Black window
• =/+ or (symbol ± invested): Light black advantage
• -+: Black winning window
• ∞: uncertain position
• +: Check
• +: Double check
• #: Checkmate

Game Phases

Two kids from a chess school, at the opening stage of the game

In the game of chess three stages are usually considered:

• The opening, which includes the first plays, where the pieces are coming out of their initial boxes.
• The middle gamewhen the two sides still have many pieces and pawns, and these come into intense conflict.
• The endwhere there are few pieces and pawns.

Each phase of the game generally requires different tactical and strategic approaches from the player. This greatly increases the complexity of the game. It can be said that chess is many games in one^{[citation needed]}: for example, playing the opening and endgame well requires different skills and it is not uncommon to find very strong players in one phase and considerably weaker ones in another.

Chess tactics and strategy

Starting between Veselin Topalov and Gata Kamski, in February 2009, in Sofia, during the World Chess Championship

Normally a game of chess is won either by checkmate, or because the opponent knows that he will inexorably receive checkmate and, therefore, resigns.

However, winning a game many times does not mean trying to checkmate the enemy king. Among strong players, on many occasions small considerations invaluable to an amateur are enough to be sure of victory. Winning positions are considered to be those in which one side can be shown to win with perfect play. Many of these positions are far from mate. A very simple example would be the following: if we eliminate the queen (or any other piece) of one of the players at the beginning of the game, it is certain that with perfect play the side that has the extra piece has a winning position. Getting the game to checkmate, however, can require dozens of moves.

Therefore, we can conclude that the goal of a player, long before checkmating, is to reach a winning position. This can be achieved in many ways. The most frequent can be included in a few classes, characterized by the type of advantage that the strong side has:

• Earn material without compensation (long the most common).
• Get a direct attack on the king.
• Get substantial positional advantages such as the destruction of the coordination of the enemy pawns or pieces, weakening the position of the opposite king, leaving on the contrary with very limited pieces in mobility, etc. These advantages should be converted later into one of the two previous advantages.

Among novice players, advantages arise spontaneously from serious mistakes, such as placing a piece on a square where it can be captured, or moving the king to an easily attackable position. But among more advanced players, the advantages can only be achieved in much more subtle ways. The procedures that have been developed to gain an advantage have been included in two main types: tactical procedures and strategic procedures.

Therefore, every advanced player knows that it is not enough to know the basic elements of the game (board, pieces and rules), but it is necessary to know and correctly apply chess tactics and strategies.

Relative value of pieces

In a game of chess, the pieces usually have a value depending on a given situation. Firstly, pieces have a static value set by their mobility, that is, the number of squares they can move regardless of the presence of other pieces in the game. the board. The mobility of the pieces is usually greater the closer they are to the center of the board, and less if they are on the edges or corners. For example, a knight in a corner can move a maximum of two squares and on an edge it can go three or five, while its maximum mobility is eight squares, when it is far from the edges of the board.

In the game, the pieces have a dynamic value according to the situation of a particular position: the presence of one's own and opponent's pieces, the squares controlled by the opponent's pieces, the lines controlled or occupied, and the possibility of carrying out strategic or positional plans. For example, a bishop is almost always more important than a knight, except in positions where immobile pawns on the bishop's side occupy squares it controls, limiting its mobility; Therefore, the knight, being able to jump over the pawns, is superior in these cases.

The material value of the pieces is a guide to evaluate a position; the knight and the bishop are often called minor pieces because of their limited reach on the board (one bishop can only go to the white-square diagonals and the other to the dark-square diagonals, while the knight has to go to a square of a different color each time it moves). The rook and queen are known as major pieces because of their superior mobility compared to the knight and bishop. The king has absolute value: if the king is lost, the game is lost; although with respect to its mobility it is assigned an intermediate value between that of the knight and the bishop.

The most usual way to determine the material value of the pieces is taking the value of the pawn as a unit. Thus, the value of the pieces is expressed in pawns: the knight and the bishop are worth 3 pawns, the rook 5 and the queen 9. With this it can be said, for example, that two rooks are worth more than a queen, or that sacrificing a knight for three pawns is an acceptable exchange, from a material point of view. It is generally accepted that the bishop pair is stronger than the knight pair.

The tactic

chess tactics is understood as the set of procedures, generally involving one or a few moves, by which a player tries to execute a simple idea on the board. The objective of a tactical maneuver is to obtain some type of advantage, among which the most characteristic is to gain material.

The white lady is nailed by the black lady.

Due to the way the pieces move, characteristic tactical maneuvers emerge. For example, the knight is capable of attacking two squares far from each other and regardless of the fact that there are many pieces around. This favors the fact that this piece can frequently make double attacks (also called forks ). As its name indicates, a double attack is one in which two pieces are attacked at the same time, so that one of them will necessarily be captured. Another example is the maneuver known as pinned where a certain piece is attacked along a row or diagonal and it turns out that it cannot retreat (“it is pinned”), since if it does, another more valuable piece behind the attacked piece on that file or diagonal would be threatened. There is also a deviation, in which a piece is forced to leave its place, where it was performing a defensive task. There are many other similar typical maneuvers, which occur very frequently and with which all players soon become familiar.

A particular type of tactical maneuver is known as combination where one of the sides, often sacrificing material, forces the other to make a series of moves with the consequence of losing the game. The goal of a meld is to gain larger advantages, such as checkmate, for the sacrificed material, or to more than win back the material later. Some combinations require a high degree of originality and fantasy, which is why they are one of the most spectacular aspects of chess. For this reason, some players, and especially former world champion Mikhail Tal, have become famous mainly for their ability to perform unexpected and tremendously complicated combinations.

The Strategy

The set of plans that a player makes in a game in the medium or long term is known as chess strategy. Strategic decisions can influence the future of a game for many moves, or even all of it.

A typical example of a strategic decision is to remove pieces in order to reach an end game. This can be advantageous on various occasions. For example, if you have a material advantage, that advantage is usually easier to exploit the fewer pieces there are. On the other hand, if the opponent has the initiative or even a strong attack, exchanging pieces can also help the initiative or attack to dissipate. The far-reaching strategic decision I must trade pieces must then be implemented by concrete, tactical means.

In chess strategy, two different types of elements are usually defined. On the one hand, there are the static elements, which influence the game for long periods. On the other hand, there are the dynamic elements, which influence during a shorter period. Often, strategic decisions consist of choosing which of all the elements is the most important. For example, it is often possible early in the opening to capture a pawn in exchange for a considerable delay in the development of the pieces. The question is when the static advantage of having more material will be offset by the dynamic advantage of having better development. This comparison between both advantages will be what will make a player risk or not perform the capture maneuver.

Typical static advantages are:

• Have more material.
• A better pawn structure.
• Control more space, especially in the center of the board.
• A better position of the king.
• Mobile pieces against pieces constrained by fixed pawns.
• Parade pair against pin and horse or two horses.

While typical dynamic advantages are:

• Better development, at the opening.
• Time win.
• Have the initiative or start an attack.
• Better coordinated pieces.
• The security of the king

A fundamental concept within chess strategy is the formulation of a game plan where the player establishes what he wishes to obtain from a position. It is in the execution of the game plan, that is, the passage from general strategic ideas to tactical execution, where the conflict between the two players arises.

Strategic decisions are also called positional decisions, and the game that develops without obvious tactical motives, in a slow and progressive way, is usually called positional game. Players are also often categorized as positional or tactical, depending on what their strongest point is.

In most cases, it can be determined by the set of openings used by a player, whether they are open or closed, the tendency to adopt positional systems where they are resolved in the long term, and minor or tactical plans for those who use openings open.

Relation between tactics and strategy

Transparent Chess

For less advanced players, the game is simply a succession of tactical episodes, often unrelated to each other. Games seem to be won or lost almost by chance, for example, by "making a bad move" that loses material. As the game progresses, however, players gain such control that the most serious bugs gradually disappear. Thereafter, the game is often decided in favor of whoever has a better understanding of how to play a certain position, a better strategic understanding.

In general, it can be said that tactics are the most important thing to be a strong player, since the calculation of concrete variations without excessive errors is essential to be able to play at a high level. However, the vast majority of chess positions are so complicated that simple calculation is not enough to guide oneself and therefore one must resort on many occasions to evaluating the existing options through a global vision of how the game will develop in the middle of the game. long term. Normally a player who is very strong strategically and weaker tactically will often use his intuition in his decisions. Very advanced players are able to develop a chess intuition that allows them to quickly rule out wrong moves with hardly any calculations.

Therefore, a great player will be one who strikes a good balance between tactics and strategy. Even so, each player has strengths and weaknesses. Even among the world champions, it is possible to point out some who possessed, above all, a highly accurate and original positional vision (José Raúl Capablanca, Alexander Alekhine, Mikhail Botvinnik, Tigran Petrosian, Anatoly Karpov) and those who stood out above all for their extraordinary tactical ability (Emanuel Lasker, Alexander Alekhine, Mikhail Tal).

Classification of players according to their strength

The strength of chess players ranges from those who barely know how to move the pieces to those who are able to play games with essentially no errors and an astonishing depth of ideas. For advanced players, a series of rankings have been established that are partly based on whether a player is able to achieve a set of minimum results in certain tournaments, against players of a predetermined level, and partly, and increasingly commonly, in their strength evaluated according to all their results and summarized in the Elo score.

This is perhaps the most widely accepted ranking of players based on their Elo rating:

1. From 0 to 1400 points: Beginning level. These players have little experience and their game is characterized by showing numerous obvious and easily detectable errors by a regular player during the game, such as placing pieces in boxes where the opponent can capture them without more or perform clearly defective openings that do not respond to any strategy or coordination.
2. Between 1400 and 1600 points: Affirmed or middle club player level. At this level players are already denoting certain knowledge of chess tactics and strategy, although these knowledge has been mostly acquired by their own experience gained during the games and not by a rigorous study of the game, which makes them incur easily detectable errors for a professional player. In the games between fans it is still common to see serious flaws such as forgetting to protect an attacked pawn or the execution of plays without any purpose. Federations or clubs usually assign an initial Elo score of 1400 to players who enter for the first time on their scale.
3. Between 1600 and 2100 Elo points: Semi-professional level or strong club player. This interval encompasses the vast majority of non-professional club players. Players at this level develop a correct chess where it is rare to find serious mistakes. Even a Grand Master will normally need many moves to kill a club player but will probably not need many to get a winning position. Club players have often read one or more chess books and are very experienced at all stages of the game, also tend to attend competitions and train and try to improve their game usually. However, they do not understand the positions that occur in the game as deeply as a teacher, and neither their tactics nor strategy is as successful as that of the latter.
4. Between 2100 and 2300 Elo points: Candidate a Maestro (CM). It is the first of the ranks recognized by the FIDE, although it does not constitute an official title. In many countries the federations recognize players with Elo greater than 2200 with the title of National Master (MN).
5. Between 2300 and 2400 points of Elo: Master FIDE (MF). Since 1978, the FIDE recognizes as Teachers the players who reach an Elo score of 2300. In November 2010, there are 5731 players with FIDE Master rank.
6. Between 2400 and 2500 Elo points: International Master (MI). Created in 1950 along with the title of Grand Master (GM), this title recognizes players whose playing force allows them to face the same level with players from other countries. Although these titles are obtained through specific results in tournaments, that of International Master can be granted in other specific ways, for example to the Youth World Champion, or to those who obtain the performance (awaited score) of an Elo 2400 player in a Chess Olympiad. There are currently 3258 active players with an International Master degree.
7. Elo from 2500 points: Grand Master (GM). Created in 1950, this title is, after the World Champion title, the greatest recognition to the best chess players. Currently some 1419 players have the rank of Grand Master. The youngest player to reach the grade of Grand Master has been the Russian Serguéi Kariakin, at the age of 12 and 7 months, in 2002.
8. Elo from 2600 points: Super Grand Master (GM). From 2600 Elo points, players who are above most Great Teachers receive unofficial names to distinguish themselves from others. It is commonly called Super Grand Master (Super-GM) to players with Elo between 2600 and 2700 points, and they are usually among the 150 or 200 best players in the world.
9. Elo from 2700 points: Candidate to World Champion. Since the establishment of the Elo list in 1970, for the next twenty years only one or two players had a score equal to or greater than 2700 points; at the end of the 1990s it was already about ten, and today it is the first fifty of the world scale. These players are the world chess elite, and are usually the participants of the highest-level tournaments, as well as the winners and qualifying tournaments of the World Championship cycle, such as the World Cup or the Candidates Tournament.
10. Elo from 2800: World Champion. Score that the world champion usually has in recent times. In May 2014, World Champion Magnus Carlsen reached an ELO of 2882, the highest score of all time.

This classification allows to determine the level of the players based on their results in chess tournaments; although they allow you to establish even higher ranges of strength, although they are no longer applicable to human players. For example, an Elo rating above 2900 is only applicable to mid-level or high-level chess programs, while an Elo rating of 3000 or higher is exclusive to the software world champion.

Cultural Impact

Playing chessJosé Gallegos and Arnosa.

Miniature of the Book of Chess, dice and tables of Alfonso X the Sabio representing a Jew (left) and a Muslim (right) playing chess.

Computers and chess

A chess game in GnuChess running in GNU/Linux

The use of systematic searches to design computer chess programs began with the work of Claude Elwood Shannon. However, we could cite as a forerunner the Spanish engineer Leonardo Torres Quevedo, who designed a finite-state automaton capable of playing rook and king endings. World champion Mikhail Botvinnik was also involved in chess program designs. However, it was not until the 1970s and 1980s of the XX century that advances in computing power and improvements in the programs led to a vast improvement in the gaming of computers. Soon they began to beat even grandmasters in rapid games and then in ordinary tournament conditions. This breakthrough culminated in the defeat of world champion Gari Kasparov by the IBM supercomputer Deep Blue, in 1997, by the score of 3.5 - 2.5. More recently, in November 2006, the Deep Fritz program, running simply on a personal computer with an Intel Core 2 Duo processor, also managed to defeat the then world champion Vladimir Kramnik by a score of 4 - 2. Today, it is assumed that the best programs, implemented in parallel on a multiprocessor computer, are considerably stronger than the best grandmasters.

In December 2017, Alphazero outperformed Stockfish 8 and other top chess programs, and Shōgi, after just twenty-four hours of play. And after four hours of play, it acquired a superhuman level. Unlike other programs, AlphaZero, the artificial intelligence created by Deep Mind, owned by Google since 2014, is not based on human knowledge. His understanding of chess, beyond the basic rules, comes solely from his self-learning ability. After playing nearly five million games over four hours against himself, AlphaZero gained the same knowledge as humans in nearly 1,400 years.

Special game modes

There are many variants of chess, obtained by changing:

• the number of players:
  • chess in consultation.
  • chess “pasapiezas”.
• the initial position of the pieces:
  • random positions like Fischer's random chess.
• the rules:
  • chess without enroque.
  • chess marsellés with two moves per turn.
  • chess loses-gana, whose goal is to be the first to lose all the pieces.
• the board:
  • Alicia's chess with double board.
  • chess hexagonal of Glinski with hexagonal board.
  • cylindrical chess
  • Three-dimensional chess.
• the game mechanism:
  • blind chess.
  • Chess postcard.
  • battle chess.

Psychological profile of chess players

The chess prodigy boy, eight-year-old Samuel Reshevsky, defeats several chess teachers, in simultaneous games in France

There is now significant psychological research on chess. One of the best established facts is that although chess is widely considered the best example of intellectual activity among games, there is very little evidence between concrete cognitive abilities and chess proficiency. Although there is a weak correlation between intelligence and chess proficiency among learning children, such a correlation does not exist when considering grandmasters or highly talented children at chess. The factor that best explains chess performance is the number of hours of chess. practice. However, it is evident that this is a highly intellectual game/sport, as it requires concentration, calculation and analytical skills, and is well known^{[by whom?]} that very high intelligence quotients abound among the world's top players. Some studies suggest that grandmasters are capable of storing between 10,000 and 100,000 "chunks", or chess-relevant board positions, although computer simulations estimate this number at 300,000.

Another aspect, less studied, is the personality of chess players. A study comparing 219 children who played chess with 50 who did not, whose personality traits were ranked according to the Big Five personality test ("O": Openness to new experiences, "C": Responsibility, "E": Extroversion, "A": Agreeableness, "N": Neuroticism), suggested that children with high scores on the "O" and "E" factors were more likely to be chess players. Boys who score higher on the "A" factor are less interested in the game. That might explain why girls, who generally score higher on the "A" factor, are generally less interested in the game. Another study carried out on university students mentions that those people whose personality makes the search and experimentation of new and strong sensations pleasurable feel much more attracted to the game than those who avoid those sensations, regardless of gender. However, the studies have not detected any correlation between personality traits and a player's chess prowess.