Chess of the position. Weaknesses in the pawn structure, such as isolated, doubled, or backward pawns and , once created, are often permanent. Care must therefore be taken to avoid these weaknesses unless they are compensated by another valuable asset (for example, by the possibility of developing an attack). 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 Defense. They are catalogued in reference works such as the "Encyclopaedia of Chess Openings". There
Tactical decision game consisted of scenarios that described situations faced by the commanders of battalions, companies, and platoons. In 1982, the Education Center of the United States Marine Corps Development and Education Command used this package as the starting point for a series of three "instructional pamphlets": "Tactical Problems for Battalion Commanders", "Tactical Problems for Platoon Leaders/Company Commanders", and "Tactical Problems for Squad Leaders". In addition to twelve problems taken from "What Now, Lieutenant?", the "Tactical Problems ..." series contained sixteen games that were written expressly for the series by Chief Warrant Officer Bryan N. Lavender, USMC. Like the scenarios in "What Now,