Ruy Lopez, Exchange Variation grandmaster play by Emanuel Lasker, and later invigorated with new ideas by Bobby Fischer. The Exchange Variation can be a powerful psychological weapon. Black is forced to play actively, which is psychologically difficult if all one needs is a draw. Lasker's famous win against Jose Raul Capablanca in the St. Petersburg 1914 chess tournament is an example of this. With a lead in the tournament, Capablanca was intent on simplifying the game to obtain a draw, but faced with the Exchange Ruy he played too passively and was routed by Lasker as a result. 4...dxc6 is the main recapture. Black's
Tactical wargame on the then-ongoing Cold War, called "Red Star/White Star: Tactical Combat in Western Europe in the 1970s". While the game was successful, Dunnigan was disappointed with it, citing difficulties in realistically portraying tactical combat in a tabletop board game. Dunnigan tried to take tactical games into a new direction in 1973 with "KampfPanzer" and "Desert War", which featured simultaneous movement, expanding on an optional rule for PanzerBlitz. Unfortunately, the quest for greater realism was having a price in complexity and "bookkeeping", or recording of moves on paper. Nonetheless, other tactical games on a man to man level were released with