Chess of the position. Weaknesses in the pawn structure, such as isolated, doubled, or backward pawns and , once created, are often permanent. Care must therefore be taken to avoid these weaknesses unless they are compensated by another valuable asset (for example, by the possibility of developing an attack). A chess opening is the group of initial moves of a game (the "opening moves"). Recognized sequences of opening moves are referred to as "openings" and have been given names such as the Ruy Lopez or Sicilian Defense. They are catalogued in reference works such as the "Encyclopaedia of Chess Openings". There
Ruy Diaz Melgarejo Ruy Diaz Melgarejo Ruy Diaz Melgarejo (Salteras 1519 – Santa Fe 1602) was a miner, military, conqueror and statesman who established the Spanish Crown in the region of Río de la Plata in South America. His life was marked by wars, conspiracies, persecutions and family conflicts. Melgarejo enjoyed the favor of the Spanish crown. He almost absolutely ruled the independent province of Guayrá for 30 years. Melgarejo left Italy on November 1, 1540, on an expedition led by Álvar Núñez Cabeza de Vaca to Río de la Plata. He remained with de Vaca until, in 1544, he was removed from