In chess , the Cambridge Springs Defense (or less commonly, the Pillsbury Variation ) is a variation of the Queen's Gambit Declined that begins with the moves:
21-558: Black breaks the pin on the h4–d8 diagonal and forms a pin of their own on the c3-knight (exploiting the absence of the White's queen bishop from the queenside ). If Black later plays dxc4, there may be threats against the g5-bishop. Note that 5.cxd5 cannot win a pawn because of the Elephant Trap . The main line continues 7.Nd2 Bb4 with the threat of ...Ne4 and pressure along the a5–e1 diagonal. The Encyclopaedia of Chess Openings code
42-462: A situational pin . A situational pin does not legally restrict the piece from moving; however, moving the pinned piece out of the line of attack can result in some detriment to the player (e.g. checkmate, immediate loss of the game, occupation of a critical square by the opponent, etc.). Consider the diagrammed position, it is White's turn to move. The black bishop on d5 is unprotected and White can capture it with 1.Nxd5; however, White should not play
63-415: A knight cannot be partially pinned due to its unique movement. The pawn is a more complex case; due to its limited and conditional movement, whether a pin on a pawn is partial depends on the line and direction of the pin and on whether there are opposing pieces available for it to capture. It is possible for two opposing pieces to be partially pinning each other. Sometimes a piece may be considered to be in
84-411: A piece that can move any number of squares along a horizontal, vertical, or diagonal line (i.e. a bishop , rook , or queen ) can pin. Any piece can be pinned except the king. The pin is one of the most powerful chess tactics. The inverse of a pin is a skewer , in which a more valuable piece under direct attack may move to expose a less valuable piece to an attack. An absolute pin is one where
105-424: A piece. White has several choices on his seventh move. The most common are: Bibliography Pin (chess) In chess , a pin is a tactic in which a defending piece cannot move out of an attacking piece's line of attack without exposing a more valuable defending piece. Moving the attacking piece to effect the pin is called pinning ; the defending piece restricted by the pin is described as pinned . Only
126-434: A rook or queen can be partially pinned along a file or rank , or a bishop or queen can be partially pinned along a diagonal . Capturing the pinning piece can still be advantageous to the pinning player, as in the example diagram (the pinning rook is defended, so capturing it with the queen would lose material ). A queen can only ever be partially pinned, as it can move in any linear direction, while
147-680: Is D52. The first recorded use of the Cambridge Springs was by Emanuel Lasker in 1892. The name derives from a 1904 tournament in Cambridge Springs , Pennsylvania , in which the defense was used several times. Practitioners of the opening have included Efim Bogoljubov , Vasily Smyslov , Garry Kasparov , and Magnus Carlsen . The line remains popular among amateurs because there are several traps White must avoid. For example, 7.Nd2 Bb4 8.Qc2 0-0 9.Bd3?? dxc4! (threatening ...Qxg5) 10.Bxf6 cxd3! (a zwischenzug ) 11.Qxd3 Nxf6 and Black has won
168-419: Is more valuable than the pinned piece. Moving such a pinned piece is legal but may not be prudent, as the shielded piece would then be vulnerable to capture. Independently of whether it is absolute or relative, a pin might be a partial pin , in which the pinned piece can still move along the line of the pin, and it might be able to capture the piece that is pinning it, but it cannot leave that line. For example,
189-426: Is out of the pinning line of attack) or as an attacker of an opposing piece (out of the pinning line). A pinned piece can still check the opposing king, however, and therefore can still defend friendly pieces against captures made by the enemy king. The act of breaking a pin is unpinning . This can be executed in a number of ways: the piece creating the pin can be captured or chased away; another unit can be moved onto
210-435: Is that in a skewer, the more valuable piece is the one under direct attack and the less valuable piece is behind it. The opponent is compelled to move the more valuable piece to avoid its capture, thereby exposing the less valuable piece which can then be captured (see chess piece relative value ). Only line pieces (i.e. bishops , rooks , and queens ) can skewer; kings , knights , and pawns cannot. Compared to
231-435: The capture or otherwise move the knight, due to the skewer attack 1...Rb1+ winning White's rook (the king is forced to move, then 2...Rxh1). It can be said that the white knight is "pinned to the b1-square" rather than pinned to a piece. A cross-pin consists of two or more pins, of any type, on the same piece. As there is only one king per side, only one of the pins can be absolute, but there are otherwise no restrictions on
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#1732851550999252-458: The game Nigel Short – Rafael Vaganian , Barcelona 1989, White sacrifices a bishop to win a queen by a skewer. White has just played 51.Be5+ (see diagram), skewering Black's king and queen. If Black responds 51...Kxe5 to avoid the immediate loss of the queen, 52.Qc3+ wins the queen by another skewer. Black resigned in this position. Skewers can be escaped by gaining a tempo with a credible threat. For example, if either defending piece leaves
273-462: The line of the pin; the unit to which a piece is pinned can be moved; or, a relatively pinned piece can be moved despite the pin, such as in the Légal Trap and the Elephant Trap . A pinning move that often occurs in openings is Bb5 which, if Black has moved ...Nc6 and ...d6 or ...d5, pins the knight on c6, since moving the knight would expose the king on e8 to check. (The same may, of course, occur on
294-411: The mate threat. Or, Black can respond by mating a different way: In this case, White cannot capture 29.gxf3 because the queen now on h2 pins the pawn to the 2nd rank. With mate being inevitable, White resigned after move 26. Bibliography Skewer (chess) In chess , a skewer is an attack upon two pieces in a line and is similar to a pin . A skewer is the opposite of a pin; the difference
315-522: The other flank , with a bishop on g5; or by Black on White, with a bishop on b4 or g4.) The diagram shows Vladimir Lenin – Maxim Gorky , Capri 1908, with White to move. Black is threatening the following rook sacrifice and forced mate : White cannot play 27.gxh3, because the queen on g3 is pinning the pawn to the g-file. The only move that postpones the mate is 27.Nf4, which temporarily blocks Black's bishop from protecting his queen, but to no avail as Black can simply play 27...Bxf4 renewing
336-413: The piece shielded by the pinned piece is the king . In this case it is illegal to move the pinned piece out of the line of attack, as that would place one's king in check (see diagram). A piece pinned in this way can still give check or defend another piece from capture by the opposing king. A relative pin is one where the piece shielded by the pinned piece is a piece other than the king, but typically
357-443: The pin, a passive action with only an implied threat, the skewer is a direct attack upon the more valuable piece, making it generally a much more powerful and effective tactic. The victim of a skewer often cannot avoid losing material ; the only question is which material will be lost. The skewer occurs less often than the pin in actual play. When it does occur, however, it is often decisive. In this diagram, with White to move,
378-405: The pinned piece cannot move out of the line of attack, the player whose piece is pinned may move other pieces to defend the pinned piece, but the pinning player may yet attack with even more pieces, etc. Using a battery of doubled rooks with a queen behind them to this end is known as Alekhine's gun . A pinned piece can usually no longer be counted on as a defender of another friendly piece (that
399-441: The skewer to give check, the other can be rescued on the next move. The skewer can also be reversed into a discovered attack ; if the less valuable piece can attack the skewering piece, making a threat with the more valuable piece allows the defender to capture the attacker first (if the threat does not itself drive off the attacker). If there is empty space between the skewering and the skewered pieces, it may be possible to convert
420-432: The types of pins involved. Pinning can also be used in combination with other tactics. For example, a piece can be pinned to prevent it from moving to attack, or a defending piece can be pinned as part of tactic undermining an opponent's defense. Another tactic which takes advantage of a pin can be called working the pin . In this tactic, other pieces from the pinning piece's side attack the opposing pinned piece. Since
441-407: The white king and queen are skewered by the black bishop. The rules of chess compel White to get out of check (if possible). After White chooses one of the handful of legal king moves available, Black will capture the white queen. In this diagram, with Black to move, the black queen and rook are skewered by White's bishop. If Black moves the queen to avoid capture, White can take the rook. In
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