How a rook moves in chess

   Each player starts with two rooks, one in each of the corners nearest their own side. In algebraic notation, White's rooks start on a1 and h1, while Black's rooks start on a8 and h8.

   The rook moves horizontally or vertically, forward or back, through any number of unoccupied squares, as in the diagram below. Like other pieces, it captures by occupying the square on which an enemy piece stands.

Ranks and files are the rooks' domain. 

The rook in conjunction with the king can perform  a special move called castling.

   In general, rooks are stronger than bishops or knights and are consequently considered about two pawns greater in value. Winning a rook for a bishop or knight is referred to as winning the exchange. Two rooks are generally considered to be worth slightly more than a queen. Rooks and queens are called heavy pieces or major pieces, as opposed to bishops and knights, which are called minor pieces (see chess piece point value).

   In the opening, the rooks are undefended by other pieces, so it is usually desirable to unite one's rooks on the first rank by castling and clearing all pieces except the king and rooks from the first rank. In that position, the rooks protect each other, and can easily move to threaten the most favorable files.

   A common goal with a rook is to place it on the first rank of an "open" file, i.e. one unobstructed by pawns of either player, or a "half-open" file, i.e. one unobstructed by friendly pawns. From this position, the rook is relatively unexposed to risk but can control every square on the file. If one file is particularly important, a player may advance one rook on it, and move the other behind, doubling the rooks.

Next: Queen moves