Castling is a defensive supermove. It is the only occasion when you move two pieces and count it as one move. Castling involves the king and one of the rooks. The player may castle either to the left with the left rook, or to the right with the right rook.
Three conditions must be met to castle on the Hexes 4P3 chess board:
• The king must not be in check.
• The king and the castling rook must not have been moved.
• If castling-right, the hex between them must be vacant and unthreatened.
Once the above conditions have been met, castle-right by moving the king next to the rook, then moving the rook to the opposite side of the king. Castle-left by swapping the positions of the rook and king. (See below.)