Ruy Lopez Ajedrez", written in 1561. Although it bears his name, this particular opening was included in the Göttingen manuscript, which dates from c. 1490. However, popular use of the Ruy Lopez opening did not develop until the mid-19th century, when Carl Jaenisch, a Russian theoretician, "rediscovered" its potential. The opening remains the most commonly used amongst the open games in master play; it has been adopted by almost all players during their careers, many of whom have played it with both colours. Due to the difficulty for Black in achieving equality, a common nickname for the opening is "The Spanish Torture".
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