This application is thoroughly crafted to assist you in reviewing and honing your opening repertoire in chess. By leveraging a sophisticated chess engine and incorporating a curated list of the most popular user moves, you can not only refine your existing repertoire but also delve into exploring new openings or strategically planning your moves within sideline variations. In addition, your progress in chess will also be aided by chess puzzles, where you'll be challenged to make moves not only for yourself but also for your opponent, adding an extra layer of strategic thinking and complexity to your training regimen. The total number of unique puzzles exceeds 100,000 to minimize the occurrence of repeated tasks for you. You can also train your knowledge of chess openings' names in an unlimited quiz mode, where with each correct answer, new names are added for you to test your knowledge. The questionnaire is structured in such a way that at the beginning, you will encounter easy questions about the most popular openings among masters. And gradually, the questions will become more challenging.