The queen (?, ?) is the most powerful piece in the game of chess, able to move any number of squares vertically, horizontally or diagonally, combining the power of the rook and bishop. Each player starts the game with one queen, placed in the middle of the first rank next to the king.

The queen is typically worth about nine pawns, which is slightly stronger than a rook and a bishop together, but slightly less strong than two rooks, though there are exceptions. It is almost always disadvantageous to exchange the queen for a single piece other than the enemy's queen.The reason that the queen is stronger than a combination of a rook and bishop, even though they control the same number of squares, is twofold. First, the queen is more mobile than the rook and the bishop, as the entire power of the queen can be transferred to another location in one move, while transferring the entire firepower of a rook and bishop requires two moves, the bishop always being restricted to squares of one color. Second, unlike the bishop, the queen is not hampered by an inability to control squares of the opposite color to the square on which it stands. A factor in favor of the rook and bishop is that they can attack (or defend) a square twice, while a queen can only do so once. However, experience has shown that this factor is usually less significant than the points favoring the queen.