Editing Castling (section)

==Strategic and tactical concepts==

===Strategy===
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|rd|  |  |qd|  |rd|kd|  
|pd|pd|  |bd|pd|pd|bd|pd
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| Position after 10.0-0-0: Opposite castling in the Yugoslav Attack
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Castling is generally an important goal in the [[Chess opening|opening]]: it moves the king to safety away from the {{chessgloss|center files}} of the board, and it moves the rook to a more active position (the f-file if castling kingside; the d-file if castling queenside).

The choice regarding to which side one castles often hinges on an assessment of the trade-off between king safety and activity of the rook. Kingside castling is generally slightly safer because the king ends up closer to the edge of the board and can usually defend all of the pawns on the castled side. In queenside castling, the king is placed closer to the center and does not defend the pawn on the a-{{chessgloss|file}}; for these reasons, the king is often subsequently moved to the b-file. In addition, queenside castling is initially obstructed by more pieces than kingside castling, thus taking longer to set up than kingside castling. On the other hand, queenside castling places the rook more efficiently on the central d-file, where it is often immediately active; meanwhile, with kingside castling, a [[Tempo (chess)|tempo]] may be required to move the rook to a more effective square.

Players may forgo castling for various reasons. In positions where the opponent cannot organize an attack against a centralized king, castling may be unnecessary or even detrimental. In addition, in certain situations, a rook can be more active near the edges of the board than in the center; for example, if it is able to fight for control of an open or semi-open file.

Kingside castling occurs more frequently than queenside castling. It is common for both players to castle kingside, less common for one player to castle kingside and the other queenside, and uncommon for both players to castle queenside. If one player castles kingside and the other queenside, it is called ''opposite castling'' or ''opposite-side castling''. Castling on opposite sides usually results in a fierce fight, as each player's pawns are free to advance to attack the opponent's castled position without exposing the player's own castled king. Opposite castling is a common feature of many openings, such as the [[Sicilian Defence, Dragon Variation, Yugoslav Attack, 9.Bc4|Yugoslav Attack]].

===Tactics involving castling===
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Tactical patterns involving castling are rare. One pattern involves castling queenside to deliver a {{chessgloss|double attack}}: the king attacks a rook (on b2 for White or b7 for Black), while the rook attacks a second enemy piece (usually the king). In the example shown, from the game [[Hermanis Matisons|Mattison]]–Millers, Königsberg 1926,<ref>{{cite web |url=https://www.chessgames.com/perl/chessgame?gid=1621031 |title=Mattison vs. Millers, Königsberg 1926 |website=[[Chessgames.com]] }}</ref> Black played 13...Rxb2{{chesspunc|??}} and resigned after 14.0-0-0+, which wins the rook.

Chess historian [[Edward Winter (chess historian)|Edward Winter]] has proposed the name "Thornton castling trap" for this pattern, in reference to the earliest known example, Thornton–Boultbee, published in the ''Brooklyn Chess Chronicle'' in 1884. Other chess writers such as [[Gary Lane (chess player)|Gary Lane]] have since adopted this term.<ref>Edward Winter, [https://www.chesshistory.com/winter/winter53.html#5914._Euwe_and_Alekhine_C.N._5907 C.N. 5916 – 'Thornton castling trap' (C.N. 4078)], 27 December 2008</ref>
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|  |  |  |rd|kd|  |nd|rd
|pd|pl|pd|  |  |  |pd|pd
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| White to play
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Another example of tactical castling is illustrated in the diagrammed position from the [[correspondence chess|correspondence]] game Gurvich–Pampin, 1976. After 1.Qxd8+ Kxd8 2.0-0-0+ Ke7 3.Nxb5, White has won a rook by castling with check and simultaneously [[Pin (chess)|unpinning]] the knight.<ref>{{cite book | author = George Huczek | title = A to Z Chess Tactics| publisher = Batsford | isbn = 978-1-8499-4446-5 | pages = 001–349 | year = 2017 }}</ref>
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{{Chess diagram
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|rd|  |bd|  |kd|  |  |rd
|pd|  |  |  |  |  |  |rl
|  |  |pd|pd|  |bd|pd|  
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|rl|nl|  |  |  |  |  |kl
| Black to play
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Such a double attack can also be made by castling kingside, although this is much rarer. In this position from the blindfold game {{nowrap|[[Sergey Karjakin|Karjakin]]–[[Magnus Carlsen|Carlsen]]}}, 2007, the move 19...0-0 threatens to win the rook on h7, as well as 20...Bxg5, when White cannot recapture due to the threat of [[back rank mate]]. Black will thus win the g5-knight next move; 20.Rh6 Bxg5 21.Rxg6+ Kh7 22.Rxg5 would not work, as it would be met by 22...Rf1{{chessAN|#}}.<ref>Tim Krabbé, [https://timkr.home.xs4all.nl/chess2/diary.htm Open chess diary], item 391</ref>
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