samedi 29 décembre 2012

Images chess 3 players


The 2013 Tata Steel Chess is taking place from 12-27 January in Wijk Aan Zee in the Netherlands.
This famous annual tournament has three separate single round-robin competitions, the A, B, and C Groups, each featuring 14 players.



The strongest tournament is the A Group and this year features 6 out of the top 10 ranked players; world champion Vishy Anand, world #1 Magnus Carlsen, defending champion Lev Aronian, rising star Fabiano Caruana, world #6 Sergey Karjakin, and US champion Hikaru Nakamura.

Chess.com has live coverage and commentary of a selection of rounds.

White starts by playing 1.e4 (moving his King's pawn two spaces). This is the most popular opening move and it has many strengths — it immediately works on controlling the center, and it frees two pieces (the queen and a bishop). The oldest openings in chess follow 1.e4. Bobby Fischer rated 1.e4 as "best by test". On the downside, 1.e4 places a pawn on an undefended square and weakens d4 and f4; the Hungarian master Gyula Breyer melodramatically declared that "After 1.e4 White's game is in its last throes". If Black mirrors White's move and replies with 1...e5, the result is an open game.
The most popular second move for White is 2.Nf3 attacking Black's king pawn, preparing for a kingside castle, and anticipating the advance of the queen pawn to d4. Black's most common reply is 2...Nc6, which usually leads to the Ruy Lopez (3.Bb5), Scotch Game (3.d4), or Italian Game (3.Bc4). If Black instead maintains symmetry and counterattacks White's center with 2...Nf6 then the Petrov's Defense results. The Philidor Defense (2...d6) is not popular in modern chess because it allows White an easy space advantage while Black's position remains cramped and passive, although solid. Other responses to 2.Nf3 are not seen in master play.
The most popular alternatives to 2.Nf3 are the Vienna Game (2.Nc3), the Bishop's Opening (2.Bc4), and the King's Gambit (2.f4). These openings have some similarities with each other, in particular the Bishop's Opening frequently transposes to variations of the Vienna Game. The King's Gambit was extremely popular in the 19th century. White sacrifices a pawn for quick development and to pull a black pawn out of the center. The Vienna Game also frequently features attacks on the Black center by means of a f2-f4 pawn advance.
In the Center Game (2.d4) White immediately opens the center but if the pawn is to be recovered after 2...exd4, White must contend with a slightly premature queen development after 3.Qxd4. An alternative is to sacrifice one or two pawns, for example in the Danish Gambit.
Many other variations after 1.e4 e5 have been studied; see Open Game for details.
1.e4 e5 Double King's Pawn Opening or Open Game
1.e4 e5 2.Nf3 Nc6 3.Bb5 Ruy Lopez
1.e4 e5 2.Nf3 Nc6 3.d4 Scotch Game
1.e4 e5 2.Nf3 Nc6 3.Bc4 Italian Game
1.e4 e5 2.Nf3 Nc6 3.Nc3 Nf6 Four Knights Game
1.e4 e5 2.Nf3 Nf6 Petrov's Defense
1.e4 e5 2.Nf3 d6 Philidor Defense
1.e4 e5 2.Nc3 Vienna Game
1.e4 e5 2.Bc4 Bishop's Opening
1.e4 e5 2.f4 King's Gambit
1.e4 e5 2.d4 exd4 3.Qxd4 Center Game
1.e4 e5 2.d4 exd4 3.c3 Danish Gambit

jeudi 27 décembre 2012

End game

The endgame (or end game or ending) is the stage of the game when there are few pieces left on the board. There are three main strategic differences between earlier stages of the game and endgame:



  • During the endgame, pawns become more important; endgames often revolve around attempting to promote a pawn by advancing it to the eighth rank.
  • The king, which has to be protected in the middlegame owing to the threat of checkmate, becomes a strong piece in the endgame. It is often brought to the center of the board where it can protect its own pawns, attack the pawns of opposite color, and hinder movement of the opponent's king.
  • Zugzwang, a disadvantage because the player has to make a move, is often a factor in endgames but rarely in other stages of the game. For example, the diagram on the right is zugzwang for both sides, as with Black to move he must play 1...Kb7 and let White promote a pawn after 2.Kd7; and with White to move he must allow a draw by 1.Kc6 stalemate or lose his last pawn by any other legal move.
Endgames can be classified according to the type of pieces that remain on board.

 Basic checkmates are positions in which one side has only a king and the other side has one or two pieces and can checkmate the opposing king, with the pieces working together with their king. For example, king and pawn endgames involve only kings and pawns on one or both sides and the task of the stronger side is to promote one of the pawns. Other more complicated endings are classified according to the pieces on board other than kings, such as the "rook and pawn versus rook endgame".

Middlegame

The middlegame is the part of the game which starts after the opening. There is no clear line between the opening and the middlegame, but typically the middlegame will start when most pieces have been developed. (Similarly, there is no clear transition from the middlegame to the endgame; see start of the endgame.) 

Because the opening theory has ended, players have to form plans based on the features of the position, and at the same time take into account the tactical possibilities of the position. The middlegame is the phase in which most combinations occur. Combinations are a series of tactical moves executed to achieve some gain. Middlegame combinations are often connected with an attack against the opponent's king; some typical patterns have their own names; for example, the Boden's Mate or the Lasker–Bauer combination.

Specific plans or strategic themes will often arise from particular groups of openings which result in a specific type of pawn structure. An example is the minority attack, which is the attack of queenside pawns against an opponent who has more pawns on the queenside. The study of openings is therefore connected to the preparation of plans that are typical of the resulting middlegames.
Another important strategic question in the middlegame is whether and how to reduce material and transition into an endgame (i.e. simplify). Minor material advantages can generally be transformed into victory only in an endgame, and therefore the stronger side must choose an appropriate way to achieve an ending. Not every reduction of material is good for this purpose; for example, if one side keeps a light-squared bishop and the opponent has a dark-squared one, the transformation into a bishops and pawns ending is usually advantageous for the weaker side only, because an endgame with bishops on opposite colors is likely to be a draw, even with an advantage of a pawn, or sometimes even with a two-pawn advantage.

Opening


Main article: Chess opening
A chess opening is the group of initial moves of a game (the "opening moves"). Recognized sequences of opening moves are referred to as openings and have been given names such as the Ruy Lopez or Sicilian Defence. They are catalogued in reference works such as the Encyclopaedia of Chess Openings. There are dozens of different openings, varying widely in character from quiet positional play (for example, the Réti Opening) to very aggressive (the Latvian Gambit). In some opening lines, the exact sequence considered best for both sides has been worked out to more than 30 moves. Professional players spend years studying openings and continue doing so throughout their careers, as opening theory continues to evolve.
The fundamental strategic aims of most openings are similar.

Development: This is the technique of placing the pieces (particularly bishops and knights) on useful squares where they will have an optimal impact on the game.
Control of the center: Control of the central squares allows pieces to be moved to any part of the board relatively easily, and can also have a cramping effect on the opponent.
King safety: It is critical to keep the king safe from dangerous possibilities. A correctly timed castling can often enhance this.
Pawn structure: Players strive to avoid the creation of pawn weaknesses such as isolated, doubled, or backward pawns, and pawn islands – and to force such weaknesses in the opponent's position.



Most players and theoreticians consider that White, by virtue of the first move, begins the game with a small advantage. This initially gives White the initiative. Black usually strives to neutralize White's advantage and achieve equality, or to develop dynamic counterplay in an unbalanced position.


 The set of openings a player has specialized in is called an opening repertoire. The main elements a player needs to consider in a repertoire are:
As White, whether to open with 1.e4, 1.d4, 1.c4, or 1.Nf3
As Black, a defense against any of these openings
A very narrow repertoire allows for deeper specialization but also makes a player less flexible to vary against different opponents. In addition, opponents may find it easier to prepare against a player with a narrow repertoire.
The main openings in a repertoire are usually reasonably sound, that is, they should lead to playable positions even against optimal counterplay. Unsound gambits are sometimes used as surprise weapons, but are unreliable for a stable repertoire. Repertoires often change as a player develops, and a player's advancement may be stifled if the opening repertoire does not evolve. Some openings which are effective against amateur players are less effective at the master level. For example Black obtains active play in return for a pawn in the Benko Gambit, amateur players may have trouble defending against Black's activity while masters are more skilled at defending and making use of the extra pawn. Some openings which are played between grandmasters are so complex and theoretical that amateur players will have trouble understanding them. An example is the Perenyi Attack of the Sicilian Defense (see diagram) which yields an immensely complicated and tactical position that even strong players have difficulty handling, and that is beyond the comprehension of most amateurs

Possibility of developing an attack

Chess strategy is concerned with evaluation of chess positions and with setting up goals and long-term plans for the future play. During the evaluation, players must take into account numerous factors such as the value of the pieces on the board, control of the center and centralization, the pawn structure, king safety, and the control of key squares or groups of squares (for example, diagonals, open files, and dark or light squares).



The most basic step in evaluating a position is to count the total value of pieces of both sides.The point values used for this purpose are based on experience; usually pawns are considered worth one point, knights and bishops about three points each, rooks about five points (the value difference between a rook and a bishop or knight being known as the exchange), and queens about nine points. The king is more valuable than all of the other pieces combined, since its checkmate loses the game. But in practical terms, in the endgame the king as a fighting piece is generally more powerful than a bishop or knight but less powerful than a rook. These basic values are then modified by other factors like position of the piece (for example, advanced pawns are usually more valuable than those on their initial squares), coordination between pieces (for example, a pair of bishops usually coordinate better than a bishop and a knight), or the type of position (knights are generally better in closed positions with many pawns while bishops are more powerful in openpositions).

Another important factor in the evaluation of chess positions is the pawn structure (sometimes known as the pawn skeleton), or the configuration of pawns on the chessboard. Since pawns are the least mobile of the chess pieces, the pawn structure is relatively static and largely determines the strategic nature of the position. Weaknesses in the pawn structure, such as isolated, doubled, or backward pawns and holes, once created, are often permanent. Care must therefore be taken to avoid these weaknesses unless they are compensated by another valuable asset (for example, by the possibility of developing an attack).

Strategy and tactics

Chess strategy consists of setting and achieving long-term positioning advantages during the game – for example, where to place different pieces – while tactics concentrate on immediate maneuver. These two parts of the chess-playing process cannot be completely separated, because strategic goals are mostly achieved by the means of tactics, while the tactical opportunities are based on the previous strategy of play. A game of chess is normally divided into three phases: opening, typically the first 10 moves, when players move their pieces to useful positions for the coming battle; then middlegame; and last the endgame, when most of the pieces are gone, kings typically take a more active part in the struggle, and pawn promotion is often decisive.

Fundamentals of tactics

In chess, tactics in general concentrate on short-term actions – so short-term that they can be calculated in advance by a human player or by a computer. The possible depth of calculation depends on the player's ability. In quiet positions with many possibilities on both sides, a deep calculation is more difficult and may not be practical, while in "tactical" positions with a limited number of forced variations, strong players can calculate long sequences of moves.


Simple one-move or two-move tactical actions – threats, exchanges of material, and double attacks – can be combined into more complicated combinations, sequences of tactical maneuvers that are often forced from the point of view of one or both players.Theoreticians described many elementary tactical methods and typical maneuvers; for example, pins, forks, skewers, batteries,discovered attacks (especially discovered checks), zwischenzugs, deflections, decoys, sacrifices, underminings, overloadings, andinterferences.

A forced variation that involves a sacrifice and usually results in a tangible gain is called a combination. Brilliant combinations – such as those in the Immortal Game – are considered beautiful and are admired by chess lovers. A common type of chess exercise, aimed at developing players' skills, is showing players a position where a decisive combination is available and challenging them to find it.

Notation for recording moves


Naming the squares in algebraic chess notation
If the piece makes a capture, "x" is inserted before the destination square. Thus Bxf3 means "bishop captures on f3". When a pawn makes a capture, the file from which the pawn departed is used in place of a piece initial, and ranks may be omitted if unambiguous. For example, exd5 (pawn on the e-file captures the piece on d5) or exd (pawn on the e-file captures a piece somewhere on the d-file).

Chess moves can be annotated with punctuation marks and other symbols. For example "!" indicates a good move, "!!" an excellent move, "?" a mistake, "??" a blunder, "!?" an interesting move that may not be best, or "?!" a dubious move, but not easily refuted.
If a pawn moves to its last rank, achieving promotion, the piece chosen is indicated after the move, for example e1Q or e1=Q. Castling is indicated by the special notations 0-0 for kingside castling and 0-0-0 for queenside castling. An en passantcapture is sometimes marked with the notation "e.p." A move that places the opponent's king in check usually has the notation "+" added. Checkmate can be indicated by "#" (occasionally "++", although this is sometimes used for a double check instead). At the end of the game, "1–0" means "White won", "0–1" means "Black won", and "½–½" indicates a draw.
For example, one variant of a simple trap known as the Scholar's mate, animated in the diagram to the left, can be recorded:
1. e4 e5
2. Qh5?! Nc6
3. Bc4 Nf6??
4. Qxf7# 1–0

End of the game

Solid white.svgabcdefghSolid white.svg
88
77
66
55
44
3e3 black bishopf3 black bishoph3 black king3
22
1h1 white king1
Solid white.svgabcdefghSolid white.svg
White is in checkmate. He cannot escape from being attacked by the Black king and bishops.
Solid white.svgabcdefghSolid white.svg
88
77
6c6 white queen6
5a5 black king5
4c4 white king4
33
22
11
Solid white.svgabcdefghSolid white.svg
Stalemate if it is Black to move. It isnot checkmate, and since Black cannot move, the game is a draw.
Although the objective of the game is to checkmate the opponent, chess games do not have to end in checkmate—either player may resign which is a win for the other player. It is considered bad etiquette to continue playing when in a truly hopeless position. If it is a game with time control, a player may run out of time and lose, even with a much superior position. Games also may end in a draw (tie). A draw can occur in several situations, including draw by agreement,stalemate, threefold repetition of a position, the fifty-move rule, or a draw by impossibility of checkmate (usually because of insufficient material to checkmate). As checkmate from some positions cannot be forced in fewer than 50 moves (such as in the pawnless chess endgameand two knights endgame), the fifty-move rule is not applied everywhere,particularly in correspondence chess.