Which of these is the most valuable piece in the game of chess?

Chess is a board game for two players. It is played in a square board, made of 64 smaller squares, with eight squares on each side. Each player starts with sixteen pieces: eight pawns, two knights, two bishops, two rooks, one queen and one king. The goal of the game is for each player to try and checkmate the king of the opponent. Checkmate is a threat ('check') to the opposing king which no move can stop. It ends the game.

The king is the most important piece in the game of chess. The king can move one square in any direction (orthogonally or diagonally), and also has a special move known as "castling". If a player's king is threatened with capture, it is said to be in check, and the player must remove the threat of capture on the next move. If this cannot be done, the king is said to be in checkmate, resulting in a loss for that player. Players cannot make any move that places their own king in check. Despite this, the king can become a strong offensive piece in the endgame, or rarely in the middlegame.

Each player begins the game with a king of their color. In algebraic notation, the king is abbreviated in English by the letter K. The white king starts the game on e1; the black king starts on e8. Unlike the other pieces, only one king per player can be on the board at any time, and the kings are never removed from the board during the game.