How to Play: Lone Number
🎯 The Goal
Shade cells so that no number appears more than once in any row or column among the unshaded cells. Unlike Sudoku, where you fill in missing numbers, Lone Number flips the script entirely. Every number is already present on the grid. Your objective is to decide which numbers to hide by shading them, using strict logical deduction rather than guessing. Because a new puzzle rotates daily—featuring a 5x5 grid for Easy mode and a 6x6 grid for Medium mode—you will always have a fresh challenge to solve.
📜 The Rules
- No Duplicates: Every unshaded row and column must contain no repeated numbers. If you spot duplicates, one must be shaded!
- No Touching: Two shaded (black) cells can never touch horizontally or vertically. You can use this rule to force logic: if you shade a cell, all four of its direct neighbors must remain unshaded.
- Stay Connected: All unshaded (white) cells must form a single continuous, connected region. No isolated groups are allowed! This connectivity constraint is crucial for late-game deductions, ensuring you never have to guess.
- Error Highlighting: Any cells that break a rule (like duplicate numbers or touching shaded cells) will automatically glow red to warn you. You can turn this off using the Hardcore Mode toggle in the settings for a pure deduction experience!
👆 The Controls
- Click once to shade a cell (eliminate it).
- Click again to mark it with a green circle (mark as known safe). This is purely a visual solving aid.
- Click a third time to return it to normal.
- 🖱️ Desktop Pro-Tip: Right-click to circle instantly!
⭐ Pro-Tips for Beginners (Start Here!)
Avoid guessing completely! Look for these logical patterns to deduce forced moves and get your first eliminations:
- The Sandwich: If you see two of the same number separated by one different number (e.g., 5 - 3 - 5), the number in the middle is ALWAYS safe (mark it with a circle). Why? Because one of the 5s MUST be shaded to avoid duplicates. If the middle number were shaded, it would touch the shaded 5, violating the 'No Touching' rule.
- The Triple: If you see three of the same number in a row (e.g., 4 - 4 - 4), the middle number is ALWAYS safe, and the two outer numbers must ALWAYS be shaded! Shading the middle one would force the outer two to be safe, leaving duplicates.
- The Pair: If you see two of the same number right next to each other, any other matching number in that row or column must be shaded to avoid duplicates. Since you can only keep one of the pair, everything else is eliminated!