Rules
Sudoku is a logic-based number puzzle played on a 9×9 grid divided into nine 3×3 boxes. The objective is simple yet challenging: fill every row, column, and 3×3 box with the numbers 1 through 9, ensuring that no number repeats within any row, column, or box. Some cells come pre-filled with numbers (called "givens" or "clues"), and your task is to deduce the remaining numbers using logic alone—no guessing required!
Deduction by Elimination
In this example, the selected cell belongs to a 3×3 box that already contains the numbers 1, 2, 3, 4, 5, 7, 8, and 9. Since each box must contain every number from 1 to 9 exactly once, the only number missing is 6—making it the only possible value for this cell. Notice how the game highlights the related row, column, and box with shaded areas, helping you visualize which numbers are already in play. This highlighting feature can be enabled in the settings to guide your solving process and make it easier to spot the constraints affecting each cell.
User-Entered Numbers
Numbers that you enter are displayed in a different style than the original clues, making it easy to distinguish between given numbers and your own entries. In this screenshot, you can see that the game also highlights all occurrences of the same number across the entire grid. This "highlight identical numbers" feature is incredibly useful for tracking where a specific digit has already been placed, helping you identify rows, columns, or boxes where that number is still needed. This visual aid significantly speeds up your solving process and reduces errors.
Applying Logic to Columns
The same elimination logic that works for boxes applies equally to rows and columns. In this example, we can see a column that contains every number from 1 to 9 except for 8. Since each column must have all nine digits without repetition, the empty cell in this column can only be filled with the number 8. By systematically checking rows, columns, and boxes for missing numbers, you can solve many cells through simple elimination—no complex techniques required!
Error Highlighting
By default, EverSudoku helps you catch obvious mistakes by highlighting duplicate numbers within the same row, column, or box. When you enter a number that already exists in a related area, both instances will be marked in red, alerting you to the conflict immediately. However, it's important to note that the game won't flag a wrong value if there's no direct contradiction—meaning you could enter an incorrect number that doesn't create a duplicate but still leads to an unsolvable puzzle. This behavior can be customized in the settings if you prefer a more challenging experience without error assistance.
Pencil Marks (Notes)
For cells where multiple numbers could potentially fit, you can use Pencil Mode to annotate possible candidates. These small notes appear in the corner of the cell and help you keep track of your deductions without committing to a final answer. EverSudoku features Smart Notes, which is enabled by default: when you place a number, the game automatically removes that digit from the pencil marks of all related cells in the same row, column, and box. This saves you time and keeps your notes accurate as you progress. If you prefer to manage your notes manually for a more traditional experience, you can disable Smart Notes in the settings.
Controls
EverSudoku is designed with an intuitive interface that makes playing enjoyable on any device. Here's how to interact with the game:
Select a Cell
Tap or click any cell on the grid to select it. The selected cell will be highlighted, and related rows, columns, and boxes will be shaded.
Enter a Number
Use the number pad at the bottom of the screen to enter a digit (1-9) into the selected cell. The number will replace any existing value.
Pencil Mode
Toggle Pencil Mode to add small candidate notes instead of final answers. Tap the same number again to remove it from the notes.
Erase
Use the eraser button to clear the selected cell, removing both the entered number and any pencil marks.
Undo
Made a mistake? Tap the undo button to revert your last action. You can undo multiple moves in sequence.
Hint
Stuck on a puzzle? Use a hint to reveal the correct number for the currently selected cell. Use hints sparingly for the best experience!
Game Modes
EverSudoku offers different game modes to match your preferred play style. Each mode adjusts the available assists and features to create a unique experience:
Standard Mode
The balanced experience for most players. Includes row/column/box highlighting, duplicate warnings, hints, and Smart Notes. Perfect for learning and casual play.
- ✓ Highlight related cells
- ✓ Highlight identical numbers
- ✓ Duplicate warnings
- ✓ Hints available
- ✓ Smart Notes enabled
Newspaper Mode
A classic pen-and-paper experience with no digital assists. No highlights, no hints, no Smart Notes—every deduction is entirely on you. For purists who want the traditional Sudoku challenge.
- ✗ No highlighting
- ✗ No duplicate warnings
- ✗ No hints
- ✗ No Smart Notes
Videogame Mode
Adds a lives system for an arcade-style experience. Make too many mistakes and it's game over! Includes error highlighting and hints to keep the action flowing.
- ✓ Lives system (3 lives)
- ✓ Error highlighting
- ✓ Hints available
- ✓ All highlights enabled
Custom Mode
Build your perfect rule set by adjusting each setting individually. Mix and match features to create exactly the experience you want.
- ✓ Fully customizable
- ✓ Toggle any feature
- ✓ Save your preferences
Settings
EverSudoku offers extensive customization options to tailor the game to your preferences. Access settings through the gear icon in the app bar.
🎨 Appearance
- Theme: Choose from Light, Dark, or Paper themes to match your preference and reduce eye strain.
- Language: Select from 11 available languages for the interface.
🎯 Gameplay Assists
- Highlight Row/Column/Box: Shade the related areas when a cell is selected.
- Highlight Identical Numbers: Show all occurrences of the selected number across the grid.
- Highlight Duplicates: Mark conflicting numbers in red when duplicates are detected.
- Show Remaining Count: Display how many of each number are left to place.
💡 Hints & Notes
- Show Hints: Enable or disable the hint button.
- Smart Notes: Automatically update pencil marks when numbers are placed.
❤️ Lives System
- Lives Enabled: Turn the lives system on or off.
- Lives Limit: Set the number of mistakes allowed (1-5).
⏱️ Timer
- Show Timer: Display or hide the elapsed time during gameplay.
Ready to Play?
Put your new knowledge to the test and start solving puzzles!
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