The application offers to solve 311 chess puzzles.After solving each of them, the opportunity opens up to watch the whole chess game, from which the position of the puzzle was obtained.The tasks are divided into 3 groups according to the main lines of such a popular opening as the Najdorf variation of the Sicilian defense. In all games of this application, the victory was achieved by the chess players who played with black pieces.Author of the idea, selection of chess games and exercises: Maxim Kuksov (MAXIMSCHOOL.RU).