Sudoku rewards patient scanning before note-taking. Every row, column, and 3x3 box needs digits 1 through 9. Notes help, but notes without a reason can turn the grid into clutter.
Scan Before Notes
Start with rows, columns, or boxes that are nearly complete. If a digit has only one possible place, fill it. If a digit has two or three possible places, then use notes to hold those options.
Tap any open cell and use the keypad or number keys. Press M or tap Notes for pencil marks. Wrong digits are rejected, so use that safety to keep solving, but do not rely on it as a guessing tool.
Keep Notes Meaningful
A good note means “this digit still has a real chance here.” If you place every possible digit in every empty square, the grid becomes harder to read. Remove notes when a row, column, or box proves they can no longer fit.
Hint reveals add time, and both best times and active board progress save on this device. Use hints when the logic has truly stalled, not before you have scanned the obvious units.
Where Grids Go Wrong
Grids go wrong when you focus on one empty cell too long. If a cell has too many possibilities, move to a more constrained row or box. Sudoku often opens from another part of the grid.
Also check repeated digits mentally before filling. A number that works in the row may still fail in the box.
One Solving Habit
For one board, scan all boxes for a single digit before adding any notes. Pick 1, then 2, and continue until the grid starts opening. For picture logic with similar mark discipline, try Nonogram. For clue counting with hidden mines, open Minesweeper.