Sicilian Defence, Chekhover Variation to: Evgeni Vasiukov vs Loek van Wely, 2002 Mikhail Tal vs Robert Eugene Byrne, 1976 Sicilian Defence, Chekhover Variation The Sicilian Defence, Chekhover Variation (also sometimes called the Szily Variation or Hungarian Variation) is a chess opening named after Vitaly Chekhover, from the game Chekhover–Lisitsin, Leningrad 1938. It is defined by the moves: On move four White ignores the standard opening principle to not develop the queen too early in the game. Although the Chekhover Variation is somewhat rare at grandmaster level, it is not uncommon among amateurs. The "Encyclopaedia of Chess Openings" (ECO) assigns code B53 to this opening.
Tactical decision game Tactical decision game A tactical decision game is a decision game that puts students in the role of the commander of a tactical unit who is faced with a challenging problem. While most tactical decision games depict problems faced by the commanders of military units, a growing number deal with the situations of types dealt with by police and firefighting organizations . The tactical decision game is known by a variety of names. These include "map problem", "tactical problem", "one-step war game", and "tactical decision exercise". Like other types of decision games, tactical decision games may either be historical or