= Rule
Violation (Duplicate/Touching)
How to Play: Lone Number
🎯 The Goal
Shade (hide) duplicate numbers so that every row and column contains only unique numbers, without breaking the grid structure! Unlike Sudoku, every number is already on the board—you use pure logic to figure out which ones must be hidden.
📜 The 3 Golden Rules
- No Duplicates: Every unshaded row and column must contain no repeated numbers.
- No Adjacent Blacks: Two shaded cells can never touch horizontally or vertically (diagonal is fine).
- Single Connected Island: All unshaded (white) cells must stay connected in a single continuous group. You cannot wall off or isolate any white cells!
👆 The Controls
- 1st Click: Shade a cell (eliminate it).
- 2nd Click: Mark with a green circle (safe). This is purely a visual aid to help you solve!
- 3rd Click: Reset to normal.
- 🖱️ Desktop Pro-Tip: Right-click to circle instantly!
🧠 3-Step Beginner Strategy
- Scan for Patterns (The 3 Givens):
• The Sandwich (X - Y - X): The middle number (Y) is ALWAYS safe (circle it).
• The Triple (X - X - X): The middle is ALWAYS safe, and the two outers must be shaded!
• The Adjacent Pair (X - X): Any other X in that same row/column must be shaded. - The "Ripple Effect": The moment you shade a cell, immediately circle its 4 direct neighbors (up, down, left, right). Since shaded cells can't touch, those neighbors are 100% safe!
- Protect the Corners: If a corner cell has two neighbors, they cannot BOTH be shaded, as this would trap the corner and break the "Connected Island" rule. If one neighbor is shaded, the corner must be circled!
Mastering Lone Number
What is a Lone Number puzzle?
Lone Number is a shading logic puzzle
played on a number grid. Your goal is to shade cells so that no number repeats in any row or
column among the visible (unshaded) cells, no two shaded cells touch each other, and all
unshaded cells remain connected in one group.
How do I know which cells to shade?
Look for rows or columns that contain
duplicate numbers — one of those duplicates must be shaded. Use the no-adjacency and
connectivity rules to narrow down which one. Start with cells that are forced by multiple
constraints at once.
What does the circle mark mean?
Clicking a cell twice marks it with a
circle, meaning you are certain it must stay unshaded. This is a solving aid — it does not
affect the puzzle logic, only helps you track your deductions visually.
Is there a new Lone Number puzzle every day?
Yes. A new puzzle rotates in
automatically each day. Easy mode uses a 5×5 grid, and Medium mode uses a 6×6 grid with a
more complex solution path.
How is Lone Number different from Sudoku?
In Sudoku you fill in missing
numbers. In Lone Number all numbers are already on the grid — your job is to decide which
ones to hide by shading. The three shading rules create a completely different style of
logical deduction.
