How to Play Sudoku: Complete Beginner's Guide to the Logic Puzzle

The rules take two minutes to learn. But the difference between a player who solves puzzles in 5 minutes and one who takes 40 minutes isn't intelligence — it's technique. Cross-hatching, pencil marks, naked pairs, hidden singles, and X-wings are the specific tools that turn a guesswork puzzle into a systematic elimination process. The step-by-step breakdowns below show exactly when and how to use each one.

Sudoku is the world's most popular logic puzzle. This complete guide walks you through the rules, strategies, and proven techniques to solve any puzzle — no math required.

The Rules of Sudoku

Sudoku is played on a 9×9 grid, which is further divided into nine 3×3 boxes (sometimes called "regions" or "blocks"). The grid starts with some cells already filled in — these are called "givens" or "clues." Your goal is to fill every empty cell with a digit from 1 to 9, following three simple rules:

• Row rule: Each row must contain the digits 1 through 9 exactly once. No repeats, no omissions.
• Column rule: Each column must contain the digits 1 through 9 exactly once.
• Box rule: Each 3×3 box must contain the digits 1 through 9 exactly once.

That's it. No arithmetic, no complex formulas — just pure logic. Every well-formed Sudoku puzzle has exactly one solution, and you can reach it without guessing if you apply the right techniques. Let's walk through them step by step.

<h2>Understanding the Grid Structure</h2>
<p>Before you make your first move, take a moment to understand how the grid is organized. The 9×9 board has three overlapping constraints:</p>
<ul>
  <li><strong>9 rows</strong> (horizontal lines, labeled 1–9 from top to bottom)</li>
  <li><strong>9 columns</strong> (vertical lines, labeled A–I from left to right)</li>
  <li><strong>9 boxes</strong> (3×3 regions, numbered 1–9 from top-left to bottom-right)</li>
</ul>
<p>Every cell belongs to exactly one row, one column, and one box. When you place a digit in a cell, it affects all three. This overlapping constraint is what makes Sudoku both challenging and satisfying — each placement ripples across the board.</p>

<figure>
  <img src="/assets/img/screenshots/sudoku-gameplay.png"
       alt="Sudoku mid-game board showing numbers filled in with pencil marks in empty cells"
       width="800" height="600" loading="lazy">
  <figcaption>A mid-game Sudoku board: filled cells constrain rows, columns, and boxes simultaneously.</figcaption>
</figure>

<h2>Your First Move: Scanning</h2>
<p>The simplest technique is <strong>scanning</strong> — looking for cells where only one digit can fit. This works best in the early stages of a puzzle, when many cells are still empty.</p>
<p><strong>How to scan:</strong></p>
<ol>
  <li>Pick a digit (say, 1) and look at all the rows, columns, and boxes where 1 is already placed.</li>
  <li>Find a row, column, or box that is missing a 1.</li>
  <li>Check the cells in that row, column, or box. If only one cell is empty and not blocked by another 1 in its row/column/box, that's where the 1 goes.</li>
</ol>
<p><strong>Example:</strong> Row 5 has 2, 3, 4, 5, 6, 7, 8, 9 — only 1 is missing. Look at the empty cell in Row 5. Check its column and box. If neither contains a 1, then that cell must be 1.</p>
<p>Scanning solves many easy puzzles by itself. For harder puzzles, you'll need more advanced techniques — but scanning is always your first tool.</p>

<h2>The Power of Cross-Hatching</h2>
<p>Cross-hatching is a more focused version of scanning. Instead of looking at the whole board, you focus on one 3×3 box at a time and systematically eliminate where each digit can go.</p>
<p><strong>Step-by-step cross-hatching:</strong></p>
<ol>
  <li>Choose a box (say, the top-left box).</li>
  <li>For each digit 1–9, ask: "Can this digit go in any empty cell in this box?"</li>
  <li>Look at the rows and columns that pass through the box. If a row already has a 5, you can't place 5 in any cell in that row within the box.</li>
  <li>Eliminate cells until only one remains — or until you've narrowed it down to a few candidates.</li>
</ol>
<p><strong>Worked example:</strong> You're looking at the top-left box. It's missing 1, 4, and 7. Row 1 has a 1, so the 1 can't go in Row 1 of that box. Column A has a 4, so the 4 can't go in Column A of that box. After eliminating, you find that 1 must go in cell B2, 4 must go in cell C3, and 7 must go in cell A1.</p>
<p>Cross-hatching is especially powerful for easy and medium puzzles. For harder puzzles, you'll combine it with pencil marks and advanced logic. For a deeper dive into intermediate strategies, check out our <a href="/guides/sudoku-strategy-from-easy-to-expert/">Sudoku strategy guide from easy to expert</a>.</p>

<h2>Mastering Pencil Marks</h2>
<p>When scanning and cross-hatching don't give you a clear answer, it's time to use <strong>pencil marks</strong> (also called "candidates" or "notes"). Pencil marks are small digits you write in a cell to track which values are still possible.</p>
<p><strong>How to use pencil marks effectively:</strong></p>
<ul>
  <li>For each empty cell, list all digits that could possibly go there (based on the row, column, and box constraints).</li>
  <li>As you solve other cells, update your pencil marks. When you place a 5 in a cell, remove 5 from the pencil marks of all cells in the same row, column, and box.</li>
  <li>When a cell's pencil are reduced to a single candidate, that's your next move.</li>
</ul>

<table>
  <caption>Example: Pencil Marks in Practice</caption>
  <thead>
    <tr>
      <th>Cell</th>
      <th>Candidates</th>
      <th>Reasoning</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>A1</td>
      <td>3, 7</td>
      <td>Row has 1,2,4,5,6,8,9; Column has 4,5,8; Box has 1,2,4,5,6,8</td>
    </tr>
    <tr>
      <td>B2</td>
      <td>1</td>
      <td>Only candidate left after cross-hatching — immediate placement</td>
    </tr>
    <tr>
      <td>C3</td>
      <td>2, 4, 7</td>
      <td>Multiple candidates; wait for more placements to narrow down</td>
    </tr>
  </tbody>
</table>

<p>In our <a href="/games/sudoku/">free Sudoku game</a>, the hint button shows pencil marks for you — use it to learn the technique before doing it manually.</p>

<h2>Advanced Techniques: Naked Pairs and Hidden Singles</h2>
<p>Once you've mastered pencil marks, you can apply more sophisticated logic. Two of the most useful advanced techniques are <strong>naked pairs</strong> and <strong>hidden singles</strong>.</p>
<p><strong>Naked pairs:</strong> If two cells in the same row, column, or box have the exact same two candidates (say, 3 and 7), then those two digits must go in those two cells — no other cell in that row/column/box can be 3 or 7. You can eliminate 3 and 7 from the pencil marks of all other cells in that group.</p>
<p><strong>Hidden singles:</strong> Sometimes a digit has only one possible cell in a row, column, or box, even if that cell has multiple candidates. For example, if 5 can only go in cell C3 within Row 3 (all other cells in Row 3 are blocked by 5s in their columns or boxes), then C3 must be 5 — even if C3's pencil marks include 2, 4, 5, and 7.</p>
<p>These techniques unlock harder puzzles. For a deeper dive, read our <a href="/guides/sudoku-strategy-from-easy-to-expert/">Sudoku strategy guide</a>, which covers naked triples, pointing pairs, X-wings, and more.</p>

<h2>Common Mistakes to Avoid</h2>
<p>Even experienced players fall into these traps:</p>
<ul>
  <li><strong>Guessing:</strong> Sudoku is pure logic. If you guess, you'll eventually reach a contradiction and have to start over. Trust the process — every cell has a logical solution.</li>
  <li><strong>Ignoring the 3×3 boxes:</strong> Beginners often focus only on rows and columns, forgetting that the box constraint also applies. Always check all three.</li>
  <li><strong>Not using pencil marks:</strong> Trying to hold all candidates in your head leads to mistakes. Write them down — our game has a built-in notes mode.</li>
  <li><strong>Giving up too early:</strong> Many puzzles have a "breakthrough moment" where one placement unlocks several others. Stick with it — the solution is always there.</li>
</ul>

<h2>Difficulty Levels Explained</h2>
<p>Sudoku puzzles are rated by the number of givens (pre-filled cells) and the complexity of techniques required:</p>
<table>
  <caption>Sudoku Difficulty Levels</caption>
  <thead>
    <tr>
      <th>Level</th>
      <th>Typical Givens</th>
      <th>Techniques Required</th>
      <th>Time to Solve</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>Easy</td>
      <td>35–45</td>
      <td>Scanning, cross-hatching</td>
      <td>5–10 minutes</td>
    </tr>
    <tr>
      <td>Medium</td>
      <td>28–34</td>
      <td>Pencil marks, naked pairs</td>
      <td>15–25 minutes</td>
    </tr>
    <tr>
      <td>Hard</td>
      <td>22–27</td>
      <td>Hidden singles, advanced logic</td>
      <td>30–60 minutes</td>
    </tr>
    <tr>
      <td>Expert</td>
      <td>17–21</td>
      <td>X-wings, swordfish, coloring</td>
      <td>60+ minutes</td>
    </tr>
  </tbody>
</table>
<p>Start with easy puzzles to build confidence, then work your way up. Our <a href="/games/sudoku/">Sudoku game</a> offers all four levels with best-time tracking.</p>

<h2>Tips for Consistent Progress</h2>
<ul>
  <li><strong>Practice daily:</strong> Even one puzzle a day builds pattern recognition. After a week, you'll notice techniques coming more naturally.</li>
  <li><strong>Time yourself:</strong> Tracking your solve time helps you measure improvement. Aim to beat your personal best, not to match others.</li>
  <li><strong>Take breaks:</strong> If you're stuck, step away for a few minutes. Fresh eyes often spot what tired eyes miss.</li>
  <li><strong>Learn one new technique per week:</strong> Start with scanning, then cross-hatching, then pencil marks, then naked pairs. Master each before moving on.</li>
</ul>

<h2>Sudoku Game Features & Controls</h2>
<p>Our online Sudoku includes several features to enhance your experience and track your progress:</p>

<h3>Statistics Panel</h3>
<p>The game tracks your performance automatically:</p>
<ul>
  <li><strong>Games Played:</strong> Total puzzles attempted</li>
  <li><strong>Games Solved:</strong> Puzzles successfully completed</li>
  <li><strong>Win Rate:</strong> Percentage of games solved (helps you gauge consistency)</li>
  <li><strong>Average Time:</strong> Your mean solving time across all games</li>
</ul>
<p>All statistics are stored locally in your browser and persist across sessions — no account required.</p>

<h3>Undo Feature</h3>
<p>Made a mistake? The undo button lets you reverse your last move. The button displays a counter showing how many undo steps remain (maximum 10 per game). Use it to correct errors or explore different solving paths without penalty.</p>

<h3>Keyboard Shortcuts</h3>
<p>Speed up your solving with these keyboard controls:</p>
<table>
  <thead>
    <tr><th>Key</th><th>Action</th><th>When Available</th></tr>
  </thead>
  <tbody>
    <tr><td>WASD or Arrow Keys</td><td>Navigate grid cells</td><td>During game</td></tr>
    <tr><td>1-9</td><td>Enter number in selected cell</td><td>During game</td></tr>
    <tr><td>Backspace / Delete</td><td>Clear selected cell</td><td>During game</td></tr>
    <tr><td>N</td><td>Start new game</td><td>Any time (even after game ends)</td></tr>
    <tr><td>R</td><td>Restart current puzzle</td><td>Any time</td></tr>
    <tr><td>M</td><td>Mute/unmute sound</td><td>Any time</td></tr>
    <tr><td>C</td><td>Check all errors (highlight incorrect cells)</td><td>During game</td></tr>
    <tr><td>Space</td><td>Pause/resume the game (shows a PAUSED overlay; press Space again to resume)</td><td>During game</td></tr>
  </tbody>
</table>

<h3>Keyboard Cursor: A Golden Border That Follows Your Arrows</h3>
<p>When you press the <strong>Arrow keys</strong> or <strong>WASD</strong> to navigate the grid, the currently focused cell is highlighted with a <strong>golden 3-pixel stroke</strong> (a bright gold border that stands out against the grid lines). This <strong>keyboard cursor</strong> — displayed as a <code>.kb-cursor</code> class in the interface — gives you a clear visual indicator of which cell will receive your next number input. Without this cursor, fast keyboard players sometimes lose track of the selected cell, especially on larger grids or during complex puzzles with many pencil marks. The golden border stays synchronized with your click selection too: whether you navigate with arrows or click with the mouse, the same golden outline always shows exactly where your next keystroke will land. This visual parity between keyboard and mouse input ensures a seamless hybrid play style — start with mouse clicks, switch to arrows for speed, and never lose your place.</p>

<h3>Check Errors Button: Instantly Highlight Every Mistake on the Board</h3>
<p>Spotted a wrong number but unsure how many other mistakes are hiding? Press <strong>C</strong> on your keyboard (or click the <strong>"Check Errors"</strong> button above the board) to instantly highlight <strong>every incorrect cell</strong> with a <strong>red pulsing outline</strong>. The error-check feature scans the entire grid, comparing your current entries against the puzzle's solution, and marks all conflicting cells simultaneously. Each flagged cell pulses with a distinctive red animation so you can immediately see the full scope of your errors at a glance.</p>
<p>The red highlights <strong>auto-clear after 3 seconds</strong>, giving you just enough time to note which cells need correction before returning to normal gameplay. This timed feedback prevents permanent visual clutter while still delivering a clear diagnostic moment. Use it strategically: rather than checking after every single entry (which slows you down), try solving an entire row or section first, then press <strong>C</strong> to verify your work in bulk. This approach builds confidence and reduces the time spent backtracking.</p>
<div class="strategy-box">
  <h4>💡 Pro Tip: Combine Keyboard Cursor + Error Check for Speed Runs</h4>
  <p>The most efficient keyboard workflow is: <strong>Arrow keys</strong> to scan the grid (watching the golden cursor), type numbers with <strong>1–9</strong>, then periodically press <strong>C</strong> to verify. The golden cursor tells you <em>where</em> you are; the error check tells you <em>whether</em> you're right. Together, they eliminate the need to visually hunt for the selected cell or manually compare entries. Advanced solvers report cutting their average solve time by 15–20% after adopting this keyboard-first workflow.</p>
</div>

💾 Auto-Save & Resume: Pick Up Exactly Where You Left Off

Life happens — the doorbell rings, a meeting starts, or you simply need a break from a challenging puzzle. Our Sudoku game includes an automatic save-and-resume system that preserves your entire game state after every single move. When you return to the page, you'll see a Resume prompt overlay displaying your elapsed time, current difficulty, how many cells you've filled, and how long ago you last played (for example, "Elapsed: 12:34 · Hard · 45 cells filled · 2 hours ago"). Click Resume to continue solving — your exact grid, numbers, pencil marks, timer, and difficulty are restored. Click New Game if you'd rather start a fresh puzzle.

The saved state lives in your browser's localStorage, meaning it survives tab closures, browser restarts, and even computer reboots. Saved games automatically expire after 7 days to keep things tidy — if you don't return within a week, the game starts fresh. When you solve the puzzle completely, the saved state is automatically cleared. This feature is especially valuable for expert-level Sudoku, where a single puzzle can take 30 minutes or more. You can solve in short bursts — during a commute, a lunch break, or between meetings — without losing any progress. Combined with the concentration-boosting benefits of puzzle games, auto-save makes it easy to maintain deep focus across multiple sessions.

🛡️ Tab Close Protection: Your Progress Is Safe

Accidentally closed the tab? No worries — our Sudoku game includes automatic tab-close protection that warns you before navigating away during an active game. When you try to close the tab, refresh the page, or click a link that takes you away while you are solving the number puzzle using logic techniques, your browser displays a confirmation dialog asking if you are sure you want to leave. This prevents accidental loss of your game progress, which is especially important for harder puzzles that take significant time to solve.

The protection activates only when a game is actively in progress (the timer is running). Once you complete or abandon a puzzle, the warning disappears so you can navigate freely. This feature works across all modern browsers including Chrome, Firefox, Safari, and Edge. For more tips on protecting your gameplay sessions, check out our Sudoku strategy guide.

Benefits of Playing Sudoku

Beyond being entertaining, Sudoku offers measurable cognitive benefits:

• Improves logical thinking: You practice deduction and inference with every puzzle.
• Enhances concentration: Sudoku requires sustained focus, which trains your attention span.
• Boosts working memory: Tracking pencil marks and possibilities strengthens short-term memory.
• Reduces stress: Focused problem-solving induces a flow state, which lowers anxiety.
• Delays cognitive decline: Studies suggest that regular puzzle-solving may help maintain cognitive function in older adults — see our guide to brain games for seniors for more.

<h2>Ready to Play?</h2>
<p>Try these strategies in our <a href="/games/sudoku/">free Sudoku game</a>. It includes three difficulty levels, built-in hints, pencil marks, and best-time tracking. No account required — just click and play.</p>
<p>For more advanced techniques, read our <a href="/guides/sudoku-strategy-from-easy-to-expert/">complete Sudoku strategy guide</a>, which covers everything from naked pairs to X-wings. And if you want to explore other types of logic puzzles, check out our guides on <a href="/guides/how-to-play-2048/">how to play 2048</a> and <a href="/guides/how-to-play-minesweeper/">how to play Minesweeper</a>.</p>

<h2>Explore More</h2>
<p>Want to deepen your puzzle skills? Check out our <a href="/guides/puzzle-games-for-beginners-complete-guide/">complete guide to puzzle games for beginners</a>, or learn <a href="/guides/how-to-improve-concentration-with-games/">how to improve concentration with games</a>. For a change of pace, try the <a href="/games/word-search/">free word search game</a> or the <a href="/games/2048/">free 2048 game</a>.</p>

<h2>🔍 Zoom Controls: Adjust the Grid Size for Your Screen</h2>
<p>Our Sudoku game includes a built-in <strong>zoom slider</strong> (🔍 icon) that scales the number grid from <strong>50% to 200%</strong>. This is particularly helpful when solving complex puzzles that require you to scan rows, columns, and boxes simultaneously — or when you need to see pencil marks clearly in individual cells. Simply drag the slider to enlarge the board on a phone screen or shrink it for a full-board overview on desktop. Your zoom preference persists via localStorage, so the grid will always appear at your last-used size.</p>
<p><strong>Recommended zoom levels:</strong></p>
<ul>
  <li><strong>Expert-level puzzles:</strong> Zoom in to 150–180% for clearer visibility of pencil marks and candidate numbers in each cell</li>
  <li><strong>Quick daily puzzles:</strong> 100% zoom on desktop provides the standard, balanced experience</li>
  <li><strong>Tablet/large screen:</strong> Zoom out to 80–90% to see the entire 9×9 grid without scrolling</li>
</ul>
<p>The zoom uses GPU-accelerated CSS transforms for smooth, jank-free adjustment. For solving techniques that benefit from a clear view of the grid, see our <a href="/guides/sudoku-strategy-from-easy-to-expert/">Sudoku strategy guide</a>.</p>

<h2>📱 Playing on Mobile: Touch Controls &amp; Haptic Feedback</h2>
<p>Our Sudoku game works seamlessly on smartphones and tablets. The board uses <strong>touch-optimized controls</strong> designed for one-handed play during commutes, lunch breaks, or quiet evenings. Here's everything mobile players need to know.</p>

<h3>Tap-to-Select: How Touch Input Works</h3>
<p>On mobile devices, you interact with the Sudoku grid using simple tap gestures:</p>
<ol>
  <li><strong>Tap any empty cell</strong> on the 9×9 board to select it. The selected cell highlights with a colored border so you know exactly where your next number will go.</li>
  <li><strong>Tap a number</strong> on the on-screen keypad (displayed below the board) to fill the selected cell with that digit.</li>
  <li><strong>Tap the same cell again</strong> to deselect it, or tap a different cell to switch your selection.</li>
</ol>
<p>This two-step tap workflow — select cell, then tap number — minimizes mis-taps on small screens. Unlike desktop keyboard input (where you press 1–9 directly), mobile tap input gives you visual confirmation before committing a digit.</p>

<h3>Haptic Feedback: Feel Your Moves</h3>
<p>When you tap a cell or enter a number, the game sends a subtle <strong>vibration pulse</strong> (5ms buzz) through your phone. This haptic feedback confirms your tap registered without requiring you to visually check the board — especially useful when solving quickly or playing with one hand. Victory sequences use a longer vibration pattern (30ms + 20ms) to celebrate puzzle completion.</p>
<p><strong>Note:</strong> Haptic feedback only works on devices with vibration hardware (most Android phones and some tablets). iPhones and iPads rely on visual feedback instead. You can mute all sounds via the <strong>M</strong> button, but haptic feedback operates independently of audio settings.</p>

<h3>Touch-Action Lock: No Accidental Scrolling</h3>
<p>During active gameplay, the Sudoku board applies <code>touch-action: none</code> — a CSS property that prevents the browser from interpreting swipe gestures as page scrolling or zooming. This means your finger won't accidentally scroll the page when you're trying to tap a cell near the edge of the screen. The lock releases automatically when you navigate away from the game or complete a puzzle.</p>

<h3>Mobile Solving Tips</h3>
<table>
  <caption>Mobile vs Desktop: Workflow Comparison</caption>
  <thead>
    <tr><th>Aspect</th><th>Desktop (Keyboard + Mouse)</th><th>Mobile (Touch)</th></tr>
  </thead>
  <tbody>
    <tr><td>Cell selection</td><td>Arrow keys or mouse click</td><td>Tap cell directly</td></tr>
    <tr><td>Number entry</td><td>Press 1–9 on keyboard</td><td>Tap number on keypad</td></tr>
    <tr><td>Undo</td><td>Ctrl+Z or click Undo button</td><td>Tap Undo button</td></tr>
    <tr><td>Pencil marks</td><td>Toggle notes mode with mouse</td><td>Tap Notes toggle, then tap numbers</td></tr>
    <tr><td>Zoom</td><td>Zoom slider (50–200%)</td><td>Zoom slider + pinch gesture</td></tr>
    <tr><td>Haptic feedback</td><td>None (visual only)</td><td>Vibration on tap (5ms buzz)</td></tr>
    <tr><td>Best for</td><td>Fast solving with keyboard shortcuts</td><td>Casual play on commutes, breaks</td></tr>
  </tbody>
</table>

<p><strong>Recommended mobile workflow:</strong> Start with the zoom slider at 120–150% for comfortable cell size. Use the digit-first approach: scan for obvious singles, tap cells, and enter numbers quickly. For harder puzzles, enable Notes mode early and tap candidate numbers into cells. The haptic feedback helps you maintain rhythm without staring at each cell. For advanced techniques like naked pairs or X-wings, zoom in to 180% to see pencil marks clearly.</p>

<h3>Keyboard Help on Touch Devices</h3>
<p>Even on mobile, you can access the <strong>keyboard help overlay</strong> by tapping the <strong>?</strong> button in the top-right corner. The overlay shows all available controls including the mobile-specific <strong>"Tap cell"</strong> gesture. Press <strong>Esc</strong> or tap outside the overlay to close it.</p>

<h2>FAQ</h2>
<h3>What are the rules of Sudoku?</h3>
<p>Fill the 9×9 grid so every row, every column, and every 3×3 box contains the digits 1–9 exactly once. Some digits are given at the start; you fill in the rest using logic. No math is involved — only deduction and elimination.</p>

<h3>What is the easiest way to start a Sudoku puzzle?</h3>
<p>Scan each row, column, and box to find cells where only one number can fit. This simple technique solves many easy puzzles by itself. For harder puzzles, combine scanning with cross-hatching and pencil marks — see our <a href="/guides/sudoku-strategy-from-easy-to-expert/">Sudoku strategy guide</a> for step-by-step instructions.</p>

<h3>Do you need math to play Sudoku?</h3>
<p>No — Sudoku uses logic, not arithmetic. The numbers are just symbols; the game is about reasoning through possibilities. That is why it is accessible to puzzle lovers of all ages, from children to seniors.</p>

<h3>Can every Sudoku be solved without guessing?</h3>
<p>Yes. Every well-formed puzzle has exactly one solution reachable by logic alone. Techniques like cross-hatching, pencil marks, naked pairs, and X-wings let you solve even expert grids without guessing — try them in our <a href="/games/sudoku/">free Sudoku game</a>.</p>

<h3>How long does it take to solve a Sudoku puzzle?</h3>
<p>It depends on difficulty and skill level. Easy puzzles take 5–10 minutes for beginners, medium puzzles 15–25 minutes, hard puzzles 30–60 minutes, and expert puzzles 60+ minutes. With practice, you'll solve them faster — our game tracks your best times so you can measure improvement.</p>

<h3>What is the difference between easy and hard Sudoku?</h3>
<p>The difference is the number of givens (pre-filled cells) and the complexity of techniques required. Easy puzzles have 35–45 givens and can be solved with basic scanning. Hard puzzles have 22–27 givens and require advanced logic like hidden singles and naked pairs. See the difficulty comparison table above for details.</p>

<h3>What statistics does the game track?</h3>
<p>The game automatically tracks your performance across sessions. You'll see your total games played, games solved, win rate percentage, and average solving time. All statistics are stored locally in your browser — no account required — and persist across devices if you use the same browser. This lets you measure improvement over time and stay motivated.</p>

<h3>What keyboard shortcuts are available?</h3>
<p>Our Sudoku game supports extensive keyboard controls for faster solving. Use <strong>WASD or arrow keys</strong> to navigate the grid, press <strong>1-9</strong> to enter numbers, and <strong>Backspace or Delete</strong> to clear a cell. Press <strong>N</strong> or <strong>R</strong> to start a new game (works even after the game ends), and <strong>M</strong> to mute or unmute sound. These shortcuts let you play efficiently without reaching for the mouse.</p>

<h3>Can I resume my Sudoku game after closing the browser?</h3>
<p>Yes. Our Sudoku game automatically saves your progress after every move — including the full grid state, your pencil marks, elapsed time, difficulty level, and undo history. When you return, a resume overlay shows your elapsed time, difficulty, how many cells you've filled, and how long ago you last played. Click <strong>Resume</strong> to continue solving, or <strong>New Game</strong> to start fresh. Saved games expire after 7 days and are automatically cleared when you complete the puzzle. This works even if you close the tab, shut down your browser, or restart your computer.</p>