Number Place

Number Placement puzzle.

A puzzle in which numbers are entered so that 1 to 9 are included in each of the vertical columns, horizontal rows, and 3x3 squares in a 9x9 frame.
You can select the difficulty level from Easy, Medium, and Hard. However, it does not necessarily indicate the degree of progress.
Guides and hints can be used, so even beginners can enjoy learning how to solve.
If you finish while answering the question, the state will be saved, so the next time, you can start from the continuation of the previous time.
Since the problem is created automatically by the algorithm unique to this application, unsolvable problems may be created.
In that case, it will be helpful to use hints and answer numbers.