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 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