SUDOKU
Sudoku, unique each time.
Puzzles with a unique solution and selectable difficulty. Click “Check” or reveal the answer anytime.
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Solution animation · elimination
Cell (1,4) is empty. Candidates: 3
What is this?
Each row, column and 3×3 box must contain 1–9 without repeats. Puzzles are guaranteed unique; blue cells are the given clues.
示例与注意事项Example & notes
一个例子A worked example
卡在中盘时点「提示」：工具用排除法找出唯一可填格，并说明理由，例如「第 3 行第 7 列只剩 6 可填」。Stuck mid-game? Press hint and it finds the only legal cell by elimination, explaining why — e.g. "row 3, column 7 can only be 6".
注意事项Things to watch
- 先找行、列、宫里只剩一个空位的格子，几乎总能填对，比硬猜省时间。Start with rows, columns or boxes that have a single empty cell — nearly always correct and far faster than guessing.
- 候选数笔记值得记：猜错后要能一步步回退，否则越猜越乱。Pencil marks are worth it: you need to be able to step back from a wrong guess.
- 难度看的是所需技巧（唯余、数对、X-Wing），不只是空格数量。Difficulty reflects the techniques required (naked singles, pairs, X-Wing), not just how many cells are empty.
相关问答More Q&A
数独一定有唯一解吗？Does every sudoku have a unique solution?
正规出版的题目保证唯一解；随机生成的题目可能有多解，正式使用前建议校验。Published puzzles guarantee a unique solution; randomly generated ones may not, so validate before use.
能打印出来做吗？Can I print the puzzle?
可以，导出后打印即可，建议留出写候选数的小空间。Yes — export and print; leave a little room for pencil marks.