Diagonal Sudoku (X-Sudoku)

Interface

Diagonal Sudoku (X-Sudoku) is a fun twist on the classic Sudoku puzzle where, in addition to rows, columns, and 3×3 boxes, both main diagonals must also contain all digits from 1 to 9.
This extra diagonal rule adds a unique layer of challenge and strategy to the game.
It’s perfect for Sudoku enthusiasts looking to test their logical thinking with a fresh variation.

Header Area

At the top of the game board, users see:

• Title:
  “Diagonal Sudoku (X-Sudoku)” — clearly showing the puzzle type.

• Timer and Control:
  A live timer (00:00) keeps track of how long you’ve been playing.
  Next to it is a Play / Pause button to start or stop the timer.

• Mistake Counter:
  Displays how many mistakes you’ve made, e.g., “Mistakes: 1/3.”
  Three mistakes end the game.

• Difficulty Selection:
  Buttons labeled Easy, Medium, Hard, Expert let you start a new puzzle of that difficulty.
  The active difficulty is highlighted in green.

Sudoku Grid

• The central 9×9 Sudoku grid appears prominently in the middle.

• Each square (cell) can contain a number from 1 to 9.

Special visual features:

• The two diagonals are sky blue with a subtle white “X” cross behind them.
  → These mark the cells affected by the diagonal rule (each diagonal must contain all digits 1–9 once).

• Fixed (preset) numbers appear in grey background — you can’t edit these.

• Empty cells are white (or dark gray in dark mode) and can be selected.

• The selected cell is highlighted in blue.

• Wrong entries briefly turn red and shake, showing a mistake.

Virtual Number Pad

To the right (or below on mobile), you’ll see a virtual keyboard:

• Buttons 1–9 for entering digits into the selected cell.

• A “Clear” button to erase the number from the selected cell.

You can also use your keyboard’s number keys (1–9) for quicker play.

Control Buttons (Below the Grid)

These help manage your gameplay:

• Hint (3 left):
  Reveals the correct number in a random empty cell (you lose some score).
  Each puzzle gives you three hints.

• New Game:
  Starts a fresh Diagonal Sudoku of the same difficulty level.

• Download PDF:
  Exports the current puzzle (unsolved grid) as a printable PDF.
  The exported PDF even includes diagonal “X” markings.

Theme Toggle🌗

Beside the title, there’s a “Dark Mode” toggle.
Clicking it instantly switches between light and dark themes —
ideal for late-night play or reducing eye strain.

Win / Lose Popups

When the game ends, a modal (popup) appears over a semi-transparent overlay:

• 🏆 Win Modal:

  • Message: “Congratulations! Well Done.”

  • Shows your time and final score.

  • Includes buttons to Share your result (using your device’s share sheet) or start a new game.

• ❌ Loss Modal:

  • Message: “Game Over! You made 3 mistakes.”

  • Includes a button to start a new game.

Both modals fade in cleanly and disable the rest of the page until closed.

Sound Feedback

• A correct sound plays when you enter a valid number.

• An error sound plays for mistakes.
  (These are optional and auto-play might depend on browser permissions.)

How to Play?

Here’s a detailed, beginner-friendly walkthrough of exactly how to play the interactive Diagonal Sudoku game on your screen. Follow these steps and you’ll be solving like a pro in no time!

1. Select a difficulty (Easy → Expert) Start by choosing your challenge level.

• Easy: 30–35 clues, perfect for warming up or casual play (5–10 minutes).
• Medium: 36–42 clues, balanced challenge for most players (10–20 minutes).
• Hard: 43–50 clues, requires stronger logic and pencil-marking (20–40 minutes).
• Expert: 51–60 clues, only a few givens—pure deduction heaven (40+ minutes). The active difficulty button glows green so you always know your current level.

2. Click Play to start the timer Tap the Play ▶️ button next to the timer (00:00). This starts the clock and officially begins your attempt. The button switches to Pause ⏸️—use it anytime to freeze the timer (great for quick breaks). Your final time directly affects your score: faster = higher points!

3. Click an empty cell to select it Tap any blank cell (white background). It instantly highlights in bright blue, showing it’s ready for input. Preset numbers (grey background) are locked—you can’t change them. The selected cell is your active workspace.

4. Use the number pad (or keyboard) to fill numbers

• Virtual pad: Tap buttons 1–9 on the right (or below on mobile).
• Physical keyboard: Just press 1–9 on your device—no need to click the pad.
• Clear button: Erases your entry from the selected cell. The game instantly checks every placement against rows, columns, boxes, and both diagonals.

5. Remember the golden rules Every move must satisfy five constraints:

• Each row → 1–9 once
• Each column → 1–9 once
• Each 3×3 box → 1–9 once
• Main diagonal (top-left → bottom-right) → 1–9 once (sky-blue cells)
• Anti-diagonal (top-right → bottom-left) → 1–9 once (also sky-blue) The subtle white “X” behind diagonal cells is your constant reminder.

6. Use hints if stuck (but they cost points!) Running into a wall? Tap Hint (3 left). The game auto-fills one correct number in a random empty cell. You get three hints per puzzle, but each deducts 200 points from your score. Use wisely—real pros aim for zero hints!

7. Avoid 3 mistakes, or the game ends Every wrong number flashes red, shakes, and increments the mistake counter. At 3 mistakes, the Game Over screen appears with a sad face. You can immediately start a fresh puzzle—no hard feelings!

8. Finish the puzzle to see your score and share your victory Fill the entire grid correctly and the Congratulations popup explodes on screen! You’ll see:

• Final time (e.g., 08:42)
• Total score (1000 base – time penalty – hint penalty + correct-entry bonus)
• Share button: Instantly post your result to WhatsApp, Twitter, Facebook, or anywhere.
• New Game button: Jump straight into another round.

Bonus Tips for Mastery

• Download the puzzle as PDF anytime for offline solving.
• Practice daily—the sky-blue diagonals train your brain to think in five dimensions!

Now grab your device, hit Play, and conquer your first Diagonal Sudoku—the clock is ticking! 🧠✨

To learn expert strategies and pattern recognition tips, visit Cracking the Cryptic — the world’s most popular Sudoku-solving channel.

Summary — User Experience Highlights