Glossary of chess

This page explains commonly used terms in chess in alphabetical order. Some of these have their own pages, like fork and pin. For a list of unorthodox chess pieces, see Fairy chess piece; for a list of terms specific to chess problems, see Glossary of chess problems; for a list of chess-related games, see Chess variants.

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

[adjective: prophylactic] Prophylactic techniques include the blockade, overprotection, and the mysterious rook move.

Q

R

S

T

U

V

W

X

Z

References

Bibliography

Rugby league positions

A rugby league football team consists of thirteen players on the field, with four substitutes on the bench. Players are divided into two general categories, forwards and backs.

Forwards are generally chosen for their size and strength. They are expected to run with the ball, to attack, and to make tackles. Forwards are required to improve the team's field position thus creating space and time for the backs. Backs are usually smaller and faster, though a big, fast player can be of advantage in the backs. Their roles require speed and ball-playing skills, rather than just strength, to take advantage of the field position gained by the forwards.

Names and numbering

The laws of the game recognise standardised numbering of positions. The starting side normally wear the numbers corresponding to their positions, only changing in the case of substitutions and position shifts during the game. In some competitions, such as Super League, players receive a squad number to use all season, no matter what positions they play in.

Center (basketball)

The center (C), also known as the five or the big man, is one of the five positions in a regulation basketball game. The center is normally the tallest player on the team, and often has a great deal of strength and body mass as well.

The tallest player to ever be drafted in the NBA or the WNBA was the 7'8" (2.33 m) Yasutaka Okayama from Japan, though he never played in the NBA. The tallest players to ever play in the NBA, at 7'7" (2.31 m), are centers Gheorghe Mureșan, and Manute Bol. Standing at 7'2" (2.18 m), Margo Dydek is the tallest player to have ever played in the WNBA.

History of the center position

Emergence of the center and the era of George Mikan

The center is considered a necessary component for a successful team, especially in professional leagues such as the NBA. Great centers have been the foundation for most of the dynasties in both the NBA and NCAA. The 6’10" (2.08 m) George Mikan pioneered the Center position, shattering the widely held perception that tall players could not develop the agility and coordination to play basketball well, and ushering in the role of the dominant big man. He led DePaul University to the NIT title, then, after turning professional, won seven National Basketball League, Basketball Association of America and NBA Championships in his ten-year career (1946–56), nine of them with the Minneapolis Lakers. Using his height to dominate opposing players, Mikan invented the hook shot and the shot block; as a consequence, the NCAA, and later NBA, adopted the goaltending rule, and, in 1951, the NBA widened the foul lane, a decision known as the 'Mikan rule'.

Graph center

The center (or Jordan center) of a graph is the set of all vertices of minimum eccentricity, that is, the set of all vertices A where the greatest distance d(A,B) to other vertices B is minimal. Equivalently, it is the set of vertices with eccentricity equal to the graph's radius. Thus vertices in the center (central points) minimize the maximal distance from other points in the graph.

Finding the center of a graph is useful in facility location problems where the goal is to minimize the worst-case distance to the facility. For example, placing a hospital at a central point reduces the longest distance the ambulance has to travel.

The concept of the center of a graph is related to the closeness centrality measure in social network analysis, which is the reciprocal of the mean of the distances d(A,B).

References

Chess

Chess is a two-player board game played on a chessboard, a checkered gameboard with 64 squares arranged in an eight-by-eight grid. Chess is played by millions of people worldwide, both amateurs and professionals.

Each player begins the game with 16 pieces: one king, one queen, two rooks, two knights, two bishops, and eight pawns. Each of the six piece types moves differently. The most powerful piece is the queen and the least powerful piece is the pawn. The objective is to 'checkmate' the opponent's king by placing it under an inescapable threat of capture. To this end, a player's pieces are used to attack and capture the opponent's pieces, while supporting their own. In addition to checkmate, the game can be won by voluntary resignation by the opponent, which typically occurs when too much material is lost, or if checkmate appears unavoidable. A game may also result in a draw in several ways.

Chess is believed to have originated in India, some time before the 7th century; the Indian game of chaturanga is also the likely ancestor of xiangqi and shogi. The pieces took on their current powers in Spain in the late 15th century; the rules were finally standardized in the 19th century.

Chess annotation symbols

When annotating chess games, commentators frequently use widely recognized annotation symbols. Question marks and exclamation points that denote a move as bad or good are ubiquitous in chess literature. Some publications intended for an international audience, such as the Chess Informant have a wide range of additional symbols that transcend language barriers.

The common symbols for evaluating the merits of a move are "??", "?", "?!", "!?", "!", and "!!". In these cases, the corresponding symbol is juxtaposed in the text immediately after the move (e.g. Re7? or Kh1!?, see algebraic chess notation).

Use of these annotation symbols is subjective, as different annotators use the same symbols differently. Moreover, an annotator's use of symbols is often influenced by the player's strength: a positional misjudgment that an annotator might give a "??" if played by a strong grandmaster might pass unremarked if played by a beginner.

Annotators' use of punctuation also may possibly be influenced by the result of the game (regardless of the actual quality of the move); one possible example came in the 11th game of the 1972 World Championship, when Spassky played an unexpected move, 14.Nb1, retreating the knight to its initial square. Spassky won the game, and several annotators gave the move two exclamation points. Edmar Mednis asserted that if Spassky had lost the game, the move would likely have been given two question marks instead.

Computer chess

Computer chess is computer architecture encompassing hardware and software capable of playing chess autonomously without human guidance. Computer chess acts as solo entertainment (allowing players to practice and to better themselves when no sufficiently strong human opponents are available), as aids to chess analysis, for computer chess competitions, and as research to provide insights into human cognition.

Current chess engines are able to defeat even the strongest human players under normal conditions. Whether computation could ever solve chess remains an open question.

Availability

Chess-playing computers are now accessible to the average consumer. From the mid-1970s to the present day, dedicated chess computers have been available for purchase. There are many chess engines such as Stockfish, Crafty, Fruit and GNU Chess that can be downloaded from the Internet for free. These engines are able to play a game that, when run on an up-to-date personal computer, can defeat most master players under tournament conditions. Top programs such as the proprietary Shredder or Fritz or the open source program Stockfish have surpassed even world champion caliber players at blitz and short time controls. In October 2008 Rybka was rated top in the CCRL,CEGT, CSS,SSDF, and WBEC rating lists and has won many recent official computer chess tournaments such as CCT 8 and 9, the 2006 Dutch Open Computer Championship, the 16th IPCCC, and the 15th World Computer Chess Championship. As of February 03, 2016, Stockfish is the top rated chess program on the IPON rating list.