In C'escacs the King can make certain special moves when he has not moved yet, as long as he is not threatened (in check). These movements are mostly evasive, but also leave the option of a capture, or advance the positioning of the Rocks. This category includes three different movements:
The movement of Rooks on the Castling must be done according to the rules of motion of this piece, an orthogonal movement, which cannot be performed if other pieces prevent it from moving.
When you play without a clock, and you want to castle, you must warn the opponent.
The simplest case is a Knight Jump move that the King can make as a first move, as long as he is not in Check. The king can even capture with his King's Leap.
The King can make this move, when:
In this move, when the above conditions are met, the King is allowed to capture an opponent's piece. It cannot be used to capture a piece that has Knight move when in Check, because this situation of Check disqualifies the King to make the move.
There are five possible hexcacs as a result of the King's Leap, which are shown in the two figures above. The five possible jumps position the King in five different columns: I, H, F, E i D. It is easy to remember the names of the columns, because they coincide, both for White's move and for Black's move, but in particular:
If we add up the five positions of the King's Leap, with the seven possible from the starting position, there are twelve different moves, which give the King great mobility in his first move, as long as he is not in check.
There are five positions resulting from the King's Leap, positions where the Castling are also defined, the only movement that allows more than one piece of the player to move simultaneously.
In Simple Castling a Rook moves to a position, so that by simultaneously making a King's Leap, the Rook and the King are positioned in adjacent (orthogonally adjacent) hexes.
This move can be made, when:
There are three possible moves on the I column with the King's Rook, and two on the D column with the Queen's Rook; on the H column there are four with the King's Rook and two with the Queen's Rook. finally in both column F and E there are two with King's and two with Queen's. In total, there are nineteen different combinations for Simple Castling.
Among the five positions that can be spanned by the King in his Leap, only three have orthogonally adjacent hexes that can be spanned by both Rooks: H, F and H. In these three King's Leaps a double castling is allowed, a move that allows all three pieces to be moved simultaneously.
In double castling both Rooks are moved using a legal move of this piece, i.e. an orthogonal move not prevented by the current position of the pieces on the board. Both Rooks must be positioned in orthogonally adjacent hexes, so that, by completing the move with the addition of the King's Leap, the King is also positioned in a hex orthogonally adjacent to both Rooks. At the end of the move, each of the three pieces is in a hex orthogonally adjacent to the other two.
This move can be made, when:
As mentioned above, there are three possible positions for the King, for a total of five different possible double castling moves.
Therefore, in addition to the seven natural movements, it incorporates a total of five King's Leap, totaling twelve positions. In the five positions of the King's Leap a castling can be made, positioning one or both Rooks in twenty-four different combinations, five of which are double castlings.