Sudoku Slate

A quiet place to solve sudoku. Sudoku Slate grades its puzzles by the hardest technique they actually require, not by counting how many digits are showing. Clue count is a poor measure. A grid with 28 clues can be trivial or brutal depending on what it asks of you, so this one asks a better question: what do you actually have to know to finish it? FOUR HONEST DIFFICULTIES Gentle needs only naked singles. A cup of tea. Steady introduces hidden singles. The everyday grid. Sharp calls for pointing and claiming. Severe requires naked and hidden pairs. If a puzzle cannot be finished by reasoning, it is thrown away rather than shipped to you. You will never need to guess, and you will never hit a wall that has no logical way through. ONE SOLUTION, ALWAYS Every puzzle is verified to have exactly one answer before it reaches you. Not usually. Every time. BUILT FOR ACTUAL SOLVING Pencil marks with a proper three-by-three layout inside each cell. Undo, as far back as you like. Tap any cell to light up its row, column, and box, with every matching digit picked out across the grid. A number pad that tells you how many of each digit are still unplaced. A timer you can pause, which pauses itself when you leave. MISTAKES ARE NOT A PUNISHMENT Three mistakes does not end your puzzle. You are offered a way to carry on. Losing twenty minutes of careful work to a counter is not our idea of a good time. QUIET BY DESIGN No cartoon celebrations. No streak nagging. No daily login rewards. Slate and indigo, serif numerals, and enough contrast to read comfortably. It is meant to feel like a well-set newspaper puzzle, not a slot machine. WORKS ANYWHERE Puzzles are generated on your device, so there is nothing to download and nothing to wait for. Play on a plane, on the underground, or with the signal off. Your progress is saved on your device. There is no account to make and nothing to sign in to. Free, supported by ads. No in-app purchases.