Ruy Lopez, Exchange Variation Qf6 7.Qd3. There are two "ECO" classifications for the Exchange Variation. Bibliography Ruy Lopez, Exchange Variation The Exchange Variation of the Ruy Lopez is a chess opening that begins with the moves: Black may recapture on c6 with either pawn; although 4...bxc6 is playable, 4...dxc6 is almost always chosen at master level. Black has gained the at the cost of a weakened pawn structure, due to his doubled pawns on c6 and c7. White aims to reach an endgame in which he has the superior pawn structure, which may become an important factor. Thus, Black is compelled to strive for
Tactical decision game fictional. If the scenario is based entirely upon a reliable historical narrative, a tactical decision game is also a "decision-forcing case". (Such an exercise may also be called an "historical map problem".) However, if any of the elements in the scenario of a tactical decision game is fictional, then the exercise is a kind of "fictional decision game". In Chapter 14 of "The Prince", Niccolò Machiavelli tells the story of the Greek general Philopoemon, who made extensive use of tactical decision games. “Philopoemon, Prince of the Achaeans, among other praises which writers have bestowed on him, is commended because in