Medium Sudoku provides just the perfect balance: there is no overabundance of hints, as in easy variants, but also no extreme difficulty. This format of puzzles makes the brain work, but does not overload it, making training effective and comfortable.
Play medium Sudoku online to analyse several variations for free, unlike simple sudoku where numbers often occur in obvious ways. It teaches: to think moves one step ahead, to eliminate wrong options, to apply advanced techniques.
Such skills are useful not only in puzzles, but also in real life, from case planning to decision making. At the medium level of Sudoku you have to keep more possible combinations in your mind, which is a great way to train your short-term memory. In addition, the player learns to notice non-obvious connections between numbers, developing attentiveness.