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sudoku

sudoku thumbnail

Game Details

Sudoku is a classic logic puzzle where you fill a 9×9 grid so each row, column, and 3×3 box contains digits 1–9 without repetition. Start with a partially filled grid and use logic to complete it. Features multiple difficulty levels, flexible timers, helper functions, puzzle management, pause/resume, light/dark themes, real-time validation, and a clean interface. Test your logical reasoning skills with this timeless puzzle challenge.

Genre: Strategy

Category: Puzzle

Platform: Browser

HOW TO PLAY

CONTROLS: - Desktop: - Mouse Click on Empty Cell: Select cell to fill - Mouse Click on Number (1-9): Place selected number in selected cell - Mouse Click on Menu Button: Open game menu - Mouse Click on Difficulty/Time Options: Choose settings - Mouse Click on Helper Buttons: Use tips, solve, refresh, restart, pause, resume - Mouse Click on Theme Toggle: Switch between light and dark themes - Mobile/Tablet: - Touch / Tap on Empty Cell: Select cell to fill - Touch / Tap on Number (1-9): Place selected number in selected cell - Touch / Tap on Menu Button: Open game menu - Touch / Tap on Options: Choose difficulty, time, and helper functions - Touch / Tap on Theme Toggle: Switch between themes BASIC MECHANICS: 1. Sudoku Rules: - 9×9 Grid: Puzzle consists of 81 cells arranged in 9 rows and 9 columns - 3×3 Boxes: Grid divided into 9 boxes, each 3×3 cells - Row Rule: Each row must contain digits 1-9 exactly once - Column Rule: Each column must contain digits 1-9 exactly once - Box Rule: Each 3×3 box must contain digits 1-9 exactly once - Pre-filled Cells: Starting puzzle has some cells already filled (clues) - Single Solution: Each puzzle has exactly one valid solution 2. Cell Selection: - Click/Tap Empty Cell: Selects cell for number placement - Selected Cell Highlight: Visual highlight shows selected cell - Deselect: Click selected cell again to deselect - Single Selection: Only one cell can be selected at a time 3. Number Selection: - Number Container: Bottom panel shows digits 1-9 - Click Number: Selects number to place in selected cell - Selected Number Highlight: Visual highlight shows selected number - Deselect Number: Click selected number again to deselect - Number Placement: Selected number placed when both cell and number selected 4. Number Placement: - Place Number: Click cell then click number (or reverse order) - Instant Validation: Number validated immediately upon placement - Correct Placement: Number accepted if correct, cell updates - Incorrect Placement: Number marked as incorrect (red highlight) - Incorrect Auto-Deselect: Incorrect numbers auto-deselect after 500ms 5. Validation System: - Real-time Validation: Checks correctness immediately - Correct Indicator: Correct numbers remain, no error marking - Incorrect Indicator: Red highlight for wrong numbers - Solution Comparison: Compares against pre-computed solution - Validation on Placement: Validates only when number placed 6. Visual Feedback: - Matching Number Highlight: Highlights all cells with same number when number selected - Selected Cell Highlight: Highlights currently selected cell - Selected Number Highlight: Highlights currently selected number - Incorrect Highlight: Red highlight for wrong entries - Green Text: Numbers filled by "Show solution" appear in green - Clear Highlights: Highlights clear when selection changes 7. Difficulty Levels: - Easy: Pre-generated easy puzzles from test cases - Medium: Pre-generated medium puzzles from test cases - Hard: Pre-generated hard puzzles from test cases - Very Hard: Dynamically generated very hard puzzles - Difficulty Selection: Choose before starting new game - Difficulty Indicator: Visual indicator shows selected difficulty 8. Time Modes: - 3 Minute Countdown: Timer counts down from 3:00 - 5 Minute Countdown: Timer counts down from 5:00 - 10 Minute Countdown: Timer counts down from 10:00 - Stopwatch Mode: Timer counts up from 0:00 - Time Selection: Choose before starting new game - Timer Display: Digital timer shows current time 9. Win Condition: - Complete Grid: All 81 cells must be filled - Valid Solution: All numbers must be correct - Countdown Mode: Must complete before timer reaches 0:00 - Stopwatch Mode: Completing puzzle wins regardless of time - Win Notification: "You won!🏆" message displayed - Win Sound: Audio plays on win - Win Alert: Alert dialog shows congratulations 10. Lose Condition: - Time Expires: Countdown timer reaches 0:00 without completion - Lose Notification: "You lost!☹️" message displayed - Lose Sound: Audio plays on loss - Lose Alert: Alert dialog shows time's up message 11. Tips System: - Tips Button: Shows all possible values for each empty cell - Candidate Display: Displays valid candidates for each cell - Toast Notification: Tips displayed in toast popup - 3 Second Display: Tips shown for 3 seconds - Console Output: Tips also printed to console - Candidate Calculation: Computes valid numbers per cell 12. Show Solution: - Solve Button: Instantly fills entire puzzle with correct solution - Green Text: Solution numbers appear in green color - Auto-Pause: Automatically pauses game when solution shown - Disables Helpers: Disables tips and solve buttons after showing solution - Solution Alert: Prompts user to try again after showing solution 13. Solve One Step: - One Step Button: Fills one empty cell with correct number - Green Text: Solved cell appears in green - Sequential Solving: Solves cells one at a time - Help Feature: Provides progressive assistance - Single Cell Focus: Fills next unsolved cell in sequence 14. Refresh Puzzle: - Refresh Button: Generates new puzzle with same difficulty - Same Difficulty: Maintains selected difficulty level - New Puzzle: Completely new puzzle generated - Resets Timer: Resets timer for new puzzle - Preserves Settings: Keeps difficulty and time mode selections 15. Restart Puzzle: - Restart Button: Clears all player entries, keeps original puzzle - Original Puzzle: Restores puzzle to starting state - Clears Attempts: Removes all numbers player placed - Resets Timer: Resets timer to initial value - Fresh Start: Allows retrying same puzzle 16. Pause System: - Pause Button: Pauses game and timer - Disables Selection: Prevents cell/number selection while paused - Pause Alert: Shows "⏸️ PAUSED" message on screen - Timer Pause: Stops countdown or stopwatch - Helper Disable: Disables tips and solve buttons while paused 17. Resume System: - Resume Button: Resumes game and timer from pause - Enables Selection: Re-enables cell/number selection - Timer Resume: Continues countdown or stopwatch - Helper Enable: Re-enables tips and solve buttons - Removes Alert: Hides pause message 18. Theme System: - Theme Toggle: Switch between light and dark themes - Light Theme: Light background with dark text - Dark Theme: Dark background with light text (green digits) - Toggle Button: Checkbox-style toggle in header - Visual Indicator: Moon/sun icons show current theme - Persists: Theme preference maintained during session 19. Grid Structure: - 9 Rows: Horizontal lines of 9 cells each - 9 Columns: Vertical lines of 9 cells each - 9 Boxes: 3×3 sub-grids within main grid - Border Styling: Visual borders separate boxes - Right Border: Vertical lines between columns 3-4 and 6-7 - Bottom Border: Horizontal lines between rows 3-4 and 6-7 20. Puzzle Generation: - Pre-generated Puzzles: Easy, Medium, Hard from test case files - Dynamic Generation: Very Hard puzzles generated algorithmically - Unique Solutions: All puzzles have exactly one valid solution - Difficulty Scaling: More empty cells = harder difficulty - Puzzle Validation: Generated puzzles verified for validity 21. Board State Management: - Current Board: Tracks current puzzle state - Solution Board: Pre-computed correct solution - Input Board: Original starting puzzle - State Updates: Board updates when numbers placed correctly - Grid Conversion: Converts between string and grid formats 22. Cell States: - Pre-filled: Cells with starting numbers (cannot be changed) - Empty: Cells available for number placement - Filled: Cells with player-placed numbers - Correct: Cells with correct numbers - Incorrect: Cells with wrong numbers (temporarily marked) 23. Audio System: - Win Sound: Plays audio-win.wav on puzzle completion - Lose Sound: Plays audio-lose.wav on time expiration - Audio Feedback: Provides audio confirmation of game end 24. Menu System: - Menu Button: Opens dropdown menu with options - Difficulty Selection: Radio buttons for difficulty levels - Time Selection: Radio buttons for time modes - Helper Functions: Buttons for tips, solve, refresh, restart - Pause/Resume: Buttons for game control - Dropdown Close: Closes when clicking outside 25. Notification System: - Snackbar Win: "You won!🏆" notification - Snackbar Lose: "You lost!☹️" notification - Toast Tips: Tips displayed in toast popup - Alert Dialogs: System alerts for game end - Auto-Hide: Notifications automatically hide after display 26. Progress Tracking: - Completion Status: Tracks which cells are filled - Validation Status: Tracks which cells are correct - Timer Progress: Shows time remaining or elapsed - Visual Progress: Grid fill progress visible 27. Helper Functions: - Tips: Shows candidates for all empty cells - Show Solution: Reveals complete solution - Solve One Step: Fills next empty cell - Refresh: Generates new puzzle - Restart: Resets current puzzle - All Disabled: Helpers disabled when game not active or paused 28. Input Methods: - Click Selection: Click cell then click number - Reverse Selection: Click number then click cell (both work) - Single Selection: Only one cell and one number selected at a time - Deselect: Click selected item again to deselect - No Keyboard Input: Mouse/touch only (no keyboard number entry) 29. Validation Logic: - Solution Comparison: Compares against pre-computed solution - Immediate Check: Validates immediately on placement - Correct Logic: Checks if placed number matches solution - Row/Column/Box Check: Implicitly validated through solution match - No Partial Validation: Only validates complete puzzle or individual placements 30. Game Flow: - Start Game: Click "New game!" button - Select Settings: Choose difficulty and time mode - Load Puzzle: Puzzle loads with spinner indicator - Play: Fill cells using click selection method - Win/Lose: Complete puzzle or run out of time - End Game: Game ends with notification and sound - Restart Options: Can refresh, restart, or start new game STRATEGIC TIPS: - Start with Obvious Cells: Look for cells with only one possible number. Scan rows, columns, and boxes for single candidates. - Eliminate Candidates: Use process of elimination. If a number appears in row/column/box, eliminate it from other cells in that region. - Box-Row-Column Interaction: Use interactions between boxes and rows/columns. If number can only go in one row of a box, eliminate it from that row in other boxes. - Pencil Marks Mentally: Think through possible candidates before placing. Tips button shows all candidates if needed. - Focus on Boxes: Often easier to complete boxes first. Look for missing numbers within each 3×3 box. - Look for Naked Singles: Cells with only one possible candidate are easiest to solve. - Hidden Singles: Numbers that can only go in one cell of a row/column/box. - Use Elimination: Eliminate impossible numbers systematically. Reduce candidates to find solutions. - Pattern Recognition: Learn common Sudoku patterns. Patterns repeat across puzzles. - Time Management: Manage time efficiently. Don't spend too long on difficult cells early. ADVANCED TECHNIQUES: - Advanced Patterns: Learn X-Wing, Swordfish, and other advanced techniques for harder puzzles. - Candidate Analysis: Use Tips function to analyze all candidates. Plan moves based on candidate elimination. - Box-Line Reduction: Use numbers that must be in specific rows/columns of boxes to eliminate candidates. - Pointing Pairs: Identify pairs that point to specific cells in rows/columns, eliminating other candidates. - Coloring Techniques: Use candidate coloring mentally to identify patterns and eliminations. - Chain Logic: Build logical chains to eliminate candidates. Connect multiple cells through logical relationships. - Multiple Solutions Check: Verify single solution property. Some techniques assume unique solution. - Efficiency Optimization: Solve puzzles with minimal use of hints. Challenge yourself to solve without tips. - Speed Solving: Practice pattern recognition for faster solving. Time yourself to improve speed. - Very Hard Mastery: Master very hard puzzles without using solve functions. Ultimate challenge completion. WINNING AND PROGRESSION: - Puzzle Completion: Complete puzzles of increasing difficulty. Each completed puzzle is an achievement. - Time Challenges: Complete puzzles within time limits. Beat time challenges for personal records. - Difficulty Progression: Progress from Easy to Very Hard. Master each difficulty level. - Speed Mastery: Improve solving speed over time. Faster completion demonstrates skill improvement. - Perfect Solving: Complete puzzles without incorrect placements. Perfect solves show mastery. - Helper Minimization: Solve puzzles with minimal use of tips and solve functions. Challenge yourself. - Pattern Mastery: Master recognition of common Sudoku patterns. Pattern knowledge accelerates solving. - Logical Reasoning: Develop logical reasoning skills. Sudoku improves critical thinking. - Consistency: Maintain consistent solving performance. Regular practice improves consistency. - Puzzle Collection: Solve many puzzles across all difficulties. Build extensive puzzle-solving experience. Enjoy solving classic Sudoku puzzles and testing your logical reasoning skills!

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