Chess strategy 10 to 25 moves, when players develop their armies and set up the stage for the coming battle; middlegame, the developed phase of the game; and endgame, when most of the pieces are gone and kings start to take an active part in the struggle. 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
Tactical decision game Lieutenant?", the games in the "Tactical Problems ..." series were based them on descriptions of actual engagements that took place between 1914 and 1953. Some of these were first-hand accounts written by S.L.A. Marshall, Erwin Rommel,and Friedrich von Mellenthin. Others were secondary works composed by military historians.) Regardless of the actual events that inspired them, all of the problems were modified to reflect the organization and equipment of the 1980s. Thus, none of these historically-inspired games can be classified as decision-forcing cases.) Tactical decision game A tactical decision game is a decision game that puts students in the role of