A free app for Android, by Chess King.
This program is the best course for beginners in chess. It includes more than 30 tactical methods, with more than 1,500 tasks. It is suitable for beginners in chess, who want to improve their skills and learn new tactics.
Each lesson is an explanation of the method, with the help of examples. The program also contains a section with more than 20 chapters, in which you can test the application.
Each chapter contains more than 30 tasks, and each task is an example.
The program contains a theoretical section, in which you can learn more about the methods of the game.
The course is an interactive one. You can not only read the text of the lessons but also to make moves on the board and work out unclear moves on the board.