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 Lopez Leko used the Marshall to win an important game against World Champion Vladimir Kramnik. Currently, Armenian Grandmaster Levon Aronian is one of the main advocates for the Marshall Attack. The main lines of the Closed Ruy Lopez continue 6.Re1 b5 7.Bb3 d6 8.c3 0-0. White can now play 9.d3 or 9.d4, but by far the most common move is 9.h3 which prepares d4 while preventing the awkward pin ...Bg4. This can be considered the main line of the opening as a whole and thousands of top-level games have reached this position. White aims to play d4 followed by Nbd2–f1–g3, which