關於這款遊戲
Play free Sudoku online, right in your browser. Fill the 9 × 9 grid so every row, column and 3 × 3 box contains the digits 1–9 exactly once. Every board is generated fresh and checked to have a single unique solution, in three levels: Easy, Standard and Hard. This sudoku with notes lets you pencil in candidates, undo and redo freely, ask for a hint or check your entries, and then replay your whole solve step by step on a timeline. Your game saves automatically, and there is no download or sign-up.
怎麼玩
- 每行、每列、每個 3 × 3 宮內，填入不重複的數字 1–9。
- 點選空格，再點選數字或使用鍵盤輸入。開啟筆記模式可記錄候選數字。
- 撤銷與重做可恢復填寫和筆記；檢查標記錯誤，提示直接填入所選格答案。
- 點選操作記錄或進入覆盤，使用時間軸、逐步按鈕或自動播放回看解題過程。返回當前遊戲可繼續填寫。
- 重新整理會恢復當前對局，最近 20 局可在本機覆盤，亦可匯出完整 JSON 記錄。
數獨技巧
- Start with singles: look for a row, column or box that is missing only one or two digits, and for cells where only one digit fits.
- Scan one digit at a time. Pick a number such as 5 and check each box for the single spot where it can still go.
- Use Notes on harder boards. When two cells in a unit share the same two candidates, those digits can be removed from the rest of that unit.
- Tap a filled number to highlight every matching digit and the cell's row, column and box, which makes conflicts easy to spot.
- Duplicates turn red right away, but a wrong digit that doesn't clash yet only shows up when you press Check. Use it sparingly to keep the challenge.
- Keyboard players: 1–9 fill, arrow keys move, N toggles Notes, Delete or Backspace erases, Ctrl / ⌘ + Z undoes and Ctrl / ⌘ + Shift + Z redoes.
玩法由來
Sudoku grew out of number-placement puzzles first published as "Number Place" in Dell puzzle magazines in the United States in 1979, usually credited to Howard Garns. The Japanese publisher Nikoli introduced them in 1984 under a name that was shortened to Sudoku, roughly "single digits", and the puzzle became a worldwide craze after British newspapers began printing it in 2004.
A proper Sudoku has exactly one solution. Mathematicians have shown that a classic 9 × 9 puzzle needs at least 17 given numbers to have a unique answer. Our generator builds a complete grid, then removes numbers one at a time, keeping a removal only if the puzzle still has a single solution. Easy, Standard and Hard differ in how many numbers are given, not in which solving techniques are required.
What makes this version different is the solve log. Every fill, note, erase, hint, check, pause, undo and redo is recorded with its time, so you can rewind to any moment of your solve and see exactly where your thinking went, including the paths you later undid.
常見問題
題目會無解或者有多個答案嗎？
每次生成棋盤都會檢查唯一解，只保留恰好一個答案的題目。輕鬆、標準和挑戰按已知數字數量分檔，並非按解題技巧評級。
撤銷後，原來的步驟還在嗎？
在。填寫、筆記、擦除、提示、檢查、暫停、撤銷及重做都會記錄時間與變更。即使撤銷後嘗試其他數字，原來的路徑也不會從覆盤中消失。
記錄會上傳或跨裝置同步嗎？
不會。當前遊戲和最近 20 局儲存在此瀏覽器，覆盤不會改變當前進度。清除瀏覽器資料會刪除存檔，建議提前匯出 JSON 備份。
計時怎麼算？
只計算實際在解題的時間。暫停、覆盤或把頁面切到後臺時都不計時。