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Todos los amantes del ajedrez, desde los exponentes de la elite internacional hasta los aficionados que dan sus primeros pasos, padecen una especie de vértigo al observar, perfectamente alineados, los treinta y dos trebejos dispuestos a ser objeto de alguna estrategia. ¿Qué jugar? ¿Qué hacer con las piezas? ¿Cómo comenzar la partida? El conocimiento de las aperturas resulta básico para responder a estos interrogantes. Cada apertura, cada variante, lleva impreso un criterio de juego, una forma de perfilar la partida. Es por esto que el contar con ideas claras respecto de los primeros movimientos permitirá concebir planes de acción y cumplirlos o modificarlos en función del juego del rival. Este curso, compuesto de tres volúmenes - sistemas cerrados, sistemas abiertos y sistemas semiabiertos -, intenta dar forma esquemática y actualizada a las aperturas y variantes más utilizadas. Entran en la categoría de sistemas abiertos todas las partidas que comienzan con 1.e4 e5, es decir el avance de dos pasos del peón de rey como primer movimiento de cada uno de los contendientes. Estos sistemas suelen conducir a posiciones clásicas de ataque y son los favoritos de los amantes del juego agresivo. La elección de aperturas abiertas implica en general un juego táctico y combinativo, pero es necesario señalar que en muchas ocasiones también permiten realizar planteos estratégicos, como es el caso de la Apertura Española. Otros ejemplos de sistemas abiertos son la Apertura Italiana, el Gambito del Rey, o la Defensa Petroff, todos ellos desarrollados en este libro.