and losing tempo. When a pawn is promoted, most of the time it is promoted to a queen. King During the middlegame, the king is often best protected in a corner behind its pawns. Such a position for either of the players is often achieved by castling by that player. If the rooks and queen leave the first rank (commonly called that player's back rank), however, an enemy rook or queen can checkmate the king by invading the first rank, commonly called a back-rank checkmate. Moving one of the pawns in front of the king (making a luft) can allow it an escape square, but may weaken the king's overall safety otherwise. One must therefore wisely balance between these trade-offs. Castling is often thought to help protect the king and often "connects" the player's two rooks together so the two rooks may protect each other. This can reduce a threat of a back-rank skewer in which the king can be skewered with capture of a rook behind it. The king can become a strong piece in the endgame. With reduced material, a quick checkmate becomes less of a concern, and moving the king towards the center of the board gives it more opportunities to make threats and actively influence play. Considerations for a successful long term deployment Chess strategy consists of setting and achieving long-term goals during the game—for example, where to place different pieces—while tactics concentrate on immediate maneuver. These two parts of chess thinking cannot be completely separated, because strategic goals are mostly achieved by the means of tactics, while the tactical opportunities are based on the previous strategy of play. Because of different strategic and tactical patterns, a game of chess is usually divided into three distinct phases: the opening, usually the first 10 to 25 moves, when players develop their armies and set up the stage for the coming battle; the middlegame, the developed phase of the game; and the endgame, when most of the pieces are gone and kings start to take an active part in the struggle. Opening A chess opening is the group of initial moves of a game (the "opening moves"). Recognized sequences of opening moves are referred to as openings and have been given names such as the Ruy Lopez or Sicilian Defence. They are catalogued in reference works such as the Encyclopaedia of Chess Openings. It is recommended for anyone