How to play & shortcuts
Fill each row, column, and 3×3 box with 1–9, once each. Bold original clues stay locked. Your entries use a different weight and theme accent. Notes hold possibilities.
Select a cell, then use the number pad or keys 1–9. Arrow keys move. Backspace or Delete erases. N toggles notes. Ctrl/⌘ Z undoes; Ctrl/⌘ Shift Z redoes.
A logical hint explains a deduction from the current board, including any candidate eliminations needed to reach a single. Check cell compares one entry with the stored answer. Reveal cell fills an answer after confirmation. Assistance is optional.
2,000 puzzles: 500 each in Easy, Moderate, Hard, and Expert. Easy uses naked singles; Moderate adds hidden singles; Hard adds locked candidates; Expert adds naked or hidden pairs and triples. All puzzles solve logically without guessing. Difficulty reflects the techniques used by our grader, rather than the number of blanks. Advanced techniques such as X-Wings are outside this collection.