Castling - the chess term which is used for the special course - shift at once of two figures as a result of which they are interchanged the position on the chessboard. As well as other courses in chess, castling has accurately established rules.
Concept of castling
The ordinary course within the game of chess means movement of one figure within the admissible algorithm of the movement on the board. In this regard castling represents the exception to the rules as during it simultaneous movement of two chessmen is carried out at once. At the same time figures which can participate in castling, are strictly defined: this is the king and the boat which is called sometimes also Tura or the tower.
In order that the chess player made the decision on commission of this course, formation of special circumstances in the course of the game which, on the one hand, do it possible according to rules of commission, and secondly is necessary, cause its expediency. The fact is that as a result of castling of the position of both figures involved in it significantly change therefore it is necessary that change of situation brought both benefit to the player.
Rules of castling
One of key rules of castling is that by the time of its implementation all figures participating in it, that is the king or the boat, have to remain on the initial places where they are since the beginning of party. If these figures already made any courses and then returned on these positions, it will be impossible to make castling. Besides, it is necessary for implementation of castling that all cages of the field between the boat and the king were free, that is on them there were no other figures.
It is known that the chessboard consists of 64 fields - on 8 in each direction. Therefore the distance from the initial position of the king to the initial position of each of boats of its color is unequal: so, between it and the right boat there are two free cages, and between it and the left boat - three cages. Therefore rules of castling define movements of the king, and movements of the boat are tied to them. So, both at right, and at the left castling the king has to move respectively to the right or left side to two cages. After that the course is carried out by the boat which has to take the position to the right of the king. It is accepted to call such castlings depending on the nature of each of them respectively queen's side and short. After that castling is considered complete. At the same time during one game of chess each player can make only one similar course therefore it is necessary to consider carefully whether its use in the circumstances is really expedient, or such opportunity should be reserved for more suitable case.