The New Sudoku Players' Forum

[Buckeye John 1976]

I know this is incredibly UNsophisticated, but some time ago I had an android version of Sudoku that allowed me to draw lines through rows and columns, allowing me to determine where a given number COULDN'T be, finding where it is (or could be) by the process of elimination. Does anyone know of a current Android version that allows the player to draw lines? Thanks in advance.

[Pupp]

I can't think off any offhand.

There are many sudoku apps that allow you to set pencil marks at the start of the puzzles.

I use Sudoku 10,000 pro set to pre-fill pencil marks. I have a neuroligical disorder that makes it hard to focus on filling in pencil marks for more difficult puzzles. (5.0 SE or higher difficulty puzzles.

Andoku 3 allows you to set it to prefill pencil marks starting at higher levels.

Either way, it's good practice to calculate your own pencil marks for several hundred puzzles when your first learning Sudoku. You lean to spot trivial techniques and fill in trivial cells that way.

In any event, if you get high enough, you can learn/practice harder techniques using puzzles that have the hardest step as the first step to solve in the puzzle. I think those are called "pearls"... Someone correct me if I'm wrong about that.

At that point, using prefilled pencil marks makes sense.

[dxSudoku]

Try Andoku 3. I'm pretty sure it does what you are asking. Although, when I solve puzzles, I use the "Compute Candidates" command to set all the possible candidates in every cell from the get-go. I just prefer solving puzzles this way.

Here's a user guide video I did on Andoku 3 if you are interested:

https://www.youtube.com/watch?v=1lj7WI9Tcsw

The video includes difficulty level definitions by puzzle-solving techniques. And it includes the instructions on how to use your smart phone's camera to scan in existing puzzles.