Sudoku hints without spoilers: get the next logical step
A useful hint should not replace the puzzle with an answer. It should narrow your attention, give you one check to make on the current grid, and let you finish the deduction yourself.
Definition
Use progressive Sudoku hints that start with where to look, explain why the move works, and leave the answer hidden until you ask for it.
One visible proof
A no-spoiler hint reveals only as much as you need: the area, then the cell, then the reason, and only finally the digit.
- 1. Start with an areaLook at row 1. It is missing only 2 and 7, so the next move can be proved there.
- 2. Narrow it to one cellCheck the first empty cell in that row against its crossing column.
- 3. Explain the reason before the answerThe crossing column already contains 2. That removes one of the row’s two missing digits.
5364891
Row 1 needs 2 and 7. Column 3 already contains 2, so the outlined cell must contain 7. The move comes from the current grid, not a guess.
Editorial method
A reference verified by Doku.su
Doku.su checks every placement or elimination in this example with its deterministic Sudoku engine. Illustrative candidates are labelled when they do not represent a complete puzzle state.
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