In chess

Chess

Chess is a two-player board game played on a chessboard, a square-checkered board with 64 squares arranged in an eight-by-eight grid. It is one of the world's most popular games, played by millions of people worldwide at home, in clubs, online, by correspondence, and in tournaments.Each player...

, the term X-ray or X-ray attack is sometimes used (1) as a synonym for skewer

Skewer (chess)

In chess, a skewer is an attack upon two pieces in a line and is similar to a pin. In fact, a skewer is sometimes described as a "reverse pin"; the difference is that in a skewer, the more valuable piece is in front of the piece of lesser or equal value...

. The term is also sometimes used to refer to a tactic

Chess tactic

In chess, a tactic refers to a sequence of moves which limits the opponent's options and may result in tangible gain. Tactics are usually contrasted with strategy, in which advantages take longer to be realized, and the opponent is less constrained in responding.The fundamental building blocks of...

 where a piece either (2) indirectly attacks an enemy piece through another piece or pieces or (3) defends a friendly piece through an enemy piece.

The second usage is seen in the position at left, which arises from the Black Knights' Tango

Black Knights' Tango

This ambitious move is playable but rarely seen. Black normally responds with 3...Ne5. Then after 4.e4 , Black struck back in the center with 4...Ng6 5.f4 e5 in the seminal game Sämisch-Torre, Moscow 1925. However, Orlov considers both Torre's fourth and fifth moves inferior...

 opening

Chess opening

A chess opening is the group of initial moves of a chess game. Recognized sequences of opening moves are referred to as openings as initiated by White or defenses, as created in reply by Black. There are many dozens of different openings, and hundreds of named variants. The Oxford Companion to...

 after 1.d4 Nf6 2.c4 Nc6 3.Nf3 e6 4.a3 d6 5.Nc3 g6!? 6.e4 Bg7 7.Be2 0-0 8.0-0 Re8 9.Be3 e5 10.d5 Nd4! Authors Richard Palliser

Richard Palliser

Richard David Palliser is an English chess player and chess writer who holds the title International Master.Palliser was joint British Rapidplay Chess Champion in 2006. He writes regularly for Everyman Chess who also employ him as an editor and advisor.His handle on the Internet Chess Club is...

 and Georgi Orlov, in their respective books on that opening, both note that Black's

White and Black in chess

In chess, the player who moves first is referred to as "White" and the player who moves second is referred to as "Black". Similarly, the pieces that each conducts are called, respectively, "the white pieces" and "the black pieces". The pieces are often not literally white and black, but some...

 rook on e8 "X-rays" White's

White and Black in chess

In chess, the player who moves first is referred to as "White" and the player who moves second is referred to as "Black". Similarly, the pieces that each conducts are called, respectively, "the white pieces" and "the black pieces". The pieces are often not literally white and black, but some...

 e-pawn through Black's own pawn on e5. If 11.Nxd4 exd4 12.Bxd4 Nxe4 13.Nxe4 Rxe4. The identical position is reached, except that White has not played a2-a3, in the King's Indian Defense after 1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 0-0 6. Be2 e5 7.0-0 Nc6 8.Be3 Re8 9.d5 Nd4!

Of the position at right, arising from the Sveshnikov Variation of the Sicilian Defense, Atanas Kolev

Atanas Kolev

Atanas Kolev is a Bulgarian Grandmaster of chess. As of July 2009, his FIDE rating is 2569. His highest rating was 2582 in July 2000-January 2001. Kolev is the coach of the Bulgarian women's national chess team...

 and Trajko Nedev observe, "On f1 the king

King (chess)

In chess, the king is the most important piece. The object of the game is to trap the opponent's king so that its escape is not possible . If a player's king is threatened with capture, it is said to be in check, and the player must remove the threat of capture on the next move. If this cannot be...

 is X-rayed by the f8-rook". They analyze the possible continuation 22...f5 23.exf5 Bxf5 24.Nxf5 Rxf5 25.Qg4 Bg5 (exploiting the pin

Pin (chess)

In chess, a pin is a situation brought on by an attacking piece in which a defending piece cannot move without exposing a more valuable defending piece on its other side to capture by the attacking piece...

 along the f-file) 26.Kg2? Bxf4 27.Nxf4 Rg5 28.Nxg6+ Kg7 and White resigned in Delchev-Kotanjian, Kusadasi 2006.
The position at left arose after 23...Qd8-h4! in Krasenkow–Seirawan, 34th Chess Olympiad

34th Chess Olympiad

The 34th Chess Olympiad, organized by the Fédération Internationale des Échecs and comprising an open and women's tournament, took place between October 28 and November 12, 2000, in Istanbul, Turkey.- Chess competition :...

, Istanbul 2000. Michael Rohde

Michael Rohde (chess player)

Michael Rohde is an American chess grandmaster.Rohde got his master rating at the age of thirteen, and gained the International Master title in 1976, followed by that of Grandmaster in 1988....

 writes of Seirawan's 23rd move, "Holding things up through an x-ray on the pawn on d4." Black would respond to either 24.e5 or 24.exd5 with 24...Qxd4+.

Gerald Abrahams

Gerald Abrahams

Gerald Abrahams was an English chess player, author and barrister.He is best known for the "Abrahams Defence" of the Semi-Slav, also known as the Abrahams-Noteboom variation:...

 alludes to the X-ray concept, without using that term, when he cites the aphorism

Aphorism

An aphorism is an original thought, spoken or written in a laconic and memorable form.The term was first used in the Aphorisms of Hippocrates...

, "Put your rook on the line of his queen

Queen (chess)

The queen is the most powerful piece in the game of chess, able to move any number of squares vertically, horizontally, or diagonally. Each player starts the game with one queen, placed in the middle of the first rank next to the king. With the chessboard oriented correctly, the white queen starts...

, no matter how many other pieces intervene." He writes, "That doggerel

Doggerel

Doggerel is a derogatory term for verse considered of little literary value. The word probably derived from dog, suggesting either ugliness, puppyish clumsiness, or unpalatability in the 1630s.-Variants:...

 jingle

Jingle

A jingle is a short tune used in advertising and for other commercial uses. The jingle contains one or more hooks and lyrics that explicitly promote the product being advertised, usually through the use of one or more advertising slogans. Ad buyers use jingles in radio and television...

 incorporates some experience". A future world champion played in that manner in Rauzer

Vsevolod Rauzer

Vsevolod Rauzer is probably best known for his extensive chess opening theory. The Richter–Rauzer Variation of the Sicilian Defence , was named in honor of him and the German master Kurt Richter....

–Botvinnik

Mikhail Botvinnik

Mikhail Moiseyevich Botvinnik, Ph.D. was a Soviet and Russian International Grandmaster and three-time World Chess Champion. Working as an electrical engineer and computer scientist at the same time, he was one of the very few famous chess players who achieved distinction in another career while...

, USSR Championship 1933. Two moves before the position at right arose, Botvinnik had played 13...Rfd8, X-raying the white queen through the pawn on d6. Now Bernard Cafferty and Mark Taimanov

Mark Taimanov

Mark Evgenievich Taimanov is a leading Soviet and Russian chess player and concert pianist.-Chess:He was awarded the International Grandmaster title in 1952 and played in the Candidates Tournament in Zurich in 1953, where he tied for eighth place. From 1946 to 1956, he was among the world's top...

 suggest "15.Qf2 to get away from the 'X-ray' attack from the d8 rook". Instead, the game continued 15.Rac1 e5! 16.b3 d5!!, exploiting the queen's position on the same file as the rook and leading to a win for Botvinnik 13 moves later.
The position at left arose from the English Opening

English Opening

In chess, the English Opening is the opening where White begins:A flank opening, it is the fourth most popular and, according to various databases, anywhere from one of the two most successful to the fourth most successful of White's twenty possible first moves. White begins the fight for the...

 in the famous miniature Petrosian

Tigran Petrosian

Tigran Vartanovich Petrosian was a Soviet-Armenian grandmaster, and World Chess Champion from 1963 to 1969. He was nicknamed "Iron Tigran" due to his playing style because of his almost impenetrable defence, which emphasised safety above all else...

–Ree

Hans Ree

Hans Ree is a Dutch Grandmaster of chess and is a columnist and chess writer for the NRC Handelsblad. He contributes to the leading chess magazines New In Chess and ChessCafe.com...

, Wijk aan Zee

Wijk aan Zee

Wijk aan Zee is a small town on the coast of the North Sea in the municipality of Beverwijk in the province of North Holland of the Netherlands. The prestigious Tata Steel chess tournament formerly Corus chess tournament and before that called Hoogovens tournament takes place there every year.Due...

 1971 after 1.c4 e5 2.Nc3 Nf6 3.Nf3 Nc6 4.g3 Bb4 5.Nd5 Nxd5 6.cxd5 e4?? 7.dxc6 exf3 8.Qb3! Author Iakov Neishtadt cites the game as an example of an "X-ray". Black resigned because the white queen's X-ray of his pawn on b7, through Black's bishop on b4, wins a piece after, e.g., 8...a5 (or 8...Qe7) 9.a3 Bc5 10.cxb7.

The above examples all involve a latent attack along a file or rank. A latent attack along a diagonal has also been called an X-ray. The position at right arose in Dorfman

Josif Dorfman

Josif Davidovich Dorfman is a Soviet-French chess Grandmaster, coach, and chess writer.-Tournament results:...

–Tseshkovsky

Vitaly Tseshkovsky

Vitaly Valerianovich Tseshkovsky is a Russian chess Grandmaster and a former champion of the USSR.Tseshkovsky was born in Siberia into a Polish family ....

, 46th USSR Championship Tbilisi

Tbilisi

Tbilisi is the capital and the largest city of Georgia, lying on the banks of the Mt'k'vari River. The name is derived from an early Georgian form T'pilisi and it was officially known as Tiflis until 1936...

 1978. Cafferty and Taimanov write, "Black can use the 'X-ray' attack of his queen on the enemy king to break up the white bastions". Black exploited the X-ray along the b8-h2 diagonal and won quickly after 48...g5! 49.hxg5 h4! with a decisive attack. The game concluded 50.g6 Kxg6 51.Qa6+ Kg5 52.gxh4+ Kxf4 53.Qc4+ Ke3+ 54.Kh3 Kf2+ 55.Qxb3 Nxg5+! and White resigned in light of 56.hxg5 Qh8#.
The third usage is given by the American master

Chess master

A chess master is a chess player of such skill that he/she can usually beat chess experts, who themselves typically prevail against most amateurs. Among chess players, the term is often abbreviated to master, the meaning being clear from context....

 and writer Bruce Pandolfini

Bruce Pandolfini

Bruce Pandolfini is a chess author, teacher and coach. He was famously portrayed by Ben Kingsley in the 1993 film Searching for Bobby Fischer, based on the book of the same name by Fred Waitzkin...

, who states that one usage of "X-Ray" is "a skewer defense along a rank, file, or diagonal" that "protects a friendly man through an enemy man in the middle along the same line of power". Jeremy Silman

Jeremy Silman

Jeremy Silman is an American International Master of chess. He has won the US Open, the American Open, and the National Open, and was the coach of the US junior national chess team...

 uses the term in the same way, illustrating "X-ray" with the two diagrams at left and right. In the diagram at left, White wins with the X-ray 1.Qxd8+! followed by 1...Rxd8 2.Rxd8+ (note how White's rook defended his queen through the Black rook on d5) Qxd8 3.Rxd8# or 1...Qxd8 2.Rxd5 Qf8 3.Rd8 and wins. In the diagram at right, White wins a pawn with 1.Nxb7!, when White's bishop on f3 defends the White knight on b7 through Black's bishop on d5. Silman states that the X-ray "takes advantage of pieces that appear to be adequately defended but really aren't".
Raymond Keene

Raymond Keene

Raymond Dennis Keene OBE is an English chess Grandmaster, a FIDE International Arbiter, a chess organiser, and a journalist and author.p196 He won the British Chess Championship in 1971, and was the first player from England to earn a Grandmaster norm, in 1974. In 1976 he became the second...

 also uses the term in this way in analyzing Fischer

Bobby Fischer

Robert James "Bobby" Fischer was an American chess Grandmaster and the 11th World Chess Champion. He is widely considered one of the greatest chess players of all time. Fischer was also a best-selling chess author...

–Bisguier

Arthur Bisguier

Arthur Bernard Bisguier is an American chess Grandmaster, chess promoter, and writer. Bisguier won two U.S. Junior Championships , three U.S. Open Chess Championship titles , and the 1954 United States Chess Championship title. He played for the United States in five chess Olympiads...

, New York 1957. Discussing a possible variation that could have arisen in that game (see position at left), Keene writes that 28.Qxg5 (when the white queen defends against 28...Qxg2# through Black's queen on g4) "defends the mate—an 'X-ray motif', as Fischer once described it".

In Euwe

Max Euwe

Machgielis Euwe was a Dutch chess Grandmaster, mathematician, and author. He was the fifth player to become World Chess Champion . Euwe also served as President of FIDE, the World Chess Federation, from 1970 to 1978.- Early years :Euwe was born in Watergraafsmeer, near Amsterdam...

-Loman, Rotterdam 1923 (diagram at right), White forced mate

Checkmate

Checkmate is a situation in chess in which one player's king is threatened with capture and there is no way to meet that threat. Or, simply put, the king is under direct attack and cannot avoid being captured...

with 17.Qh8+! Bxh8 18.Rxh8#. Neishtadt writes of 17.Qh8+, "The X-ray! The bishop at b2 attacks the square h8 'through' the enemy bishop."