Sudoku Techniques

All the problems included in this applicatin are only logically solvable.
There is no need to use a "trial and error", or the "temporary placement".
However, it is only for advanced users.
For this reason, it may seem difficult for those who are not used to it, but this application has a lot of hint and support functions.
That is not the answer itself, but rather hints that say, "Oh! I see." Gradually, you will learn the techniques.
Train your math brain with this application and aim to be able to solve it on your own without using any hints.