SudoKoach doesn't solve the puzzle for you, it simply figures out which numbers are possible in each unsolved cell. This task is neither difficult nor challenging, if you've solved Sudoku puzzles before, you know that it is boring, time-consuming, and error-prone, but absolutely necessary. You don't need to waste your effort on this step. Instead, you can immediately get to the fun part of solving Sudoku puzzles: looking for the relationships among cells that indicate solutions.