One Line Puzzle
Draw one continuous line through every white square. Start at the circle, weave around the gaps, and leave the diamond for the final move. The first boards let you learn reverse tracing; later boards ask you to protect connections between larger areas.
How to play
- Find the circle and diamond. Only active white squares count toward completion.
- Drag from the head or tap an adjacent square. You can also use the arrow keys.
- Visit each active square once and finish at the diamond. Entering it before the remaining squares is not allowed.
- If you reconsider a turn, trace backward along the line or use Undo. Restart is always free.
What changes across 210 levels?
All rounds use an 8 × 8 canvas. The first five boards have 6, 12, 16, 22 and 26 active squares. The first round ends with 40-square puzzles; the second round varies gaps and endpoints across 40 to 50 active squares. The third round uses 50 to 56 active squares across wider layouts, with new gaps and connections. The fourth round uses 52 to 58 squares on full-width layouts, with different gaps and endpoints to connect. The fifth round revisits 54 to 58 squares with new gaps and endpoints, keeping several route choices open as you draw. The sixth round covers 56 to 60 active squares, with fewer gaps and longer routes across connected regions. The seventh round varies 56 to 60 squares across new shapes, with a different order of connected regions to explore. Every board has a verified complete route, and multiple solutions are allowed.
Plan the connections
Look for areas joined by a narrow passage. Before entering a pocket, consider how the line can leave it. While a legal forward move exists the game lets you explore, even if an earlier turn has made completion impossible. The delayed stuck reminder does not reveal the earlier decision.
Find a puzzle to practice
Easy, Medium and Hard are editorial campaign bands, rather than measured player solve rates. The topic collections group actual rules and board features.
Easy One Line Puzzles
Start with the first 10 One Line Puzzle boards: compact shapes, free tracing back and clear circle-to-diamond goals.
Medium One Line Puzzles
Explore One Line Puzzle levels 11–30, with 32–40 active squares, missing cells and longer connections to preserve.
Hard One Line Puzzles
Try One Line Puzzle levels 31–210: 40–60 squares across wider layouts, with verified routes and free backtracking.
One Line Puzzles with Free Backtracking
Practice revising a continuous route in One Line Puzzle. Undo or trace backward through 210 boards without lives, move caps or retry penalties.
One Line Puzzles around Missing Squares
Find One Line Puzzle boards with interior gaps. Learn to keep pockets connected while covering every active square before the diamond.
Questions about these puzzles
How do I finish a One Line Puzzle?
Start at the circle, cover every active square by moving up, down, left or right, and reach the diamond last. Grey squares cannot be entered, and older visited squares cannot be crossed.
Can I change my route?
Yes. Trace to the preceding square, use Undo or Backspace, or Restart freely. There is no timer, life limit or retry penalty.
How are hints and stuck reminders different?
Hint is requested by you and can highlight one next square on a solvable route. Each level has 3 next-square hints. Rechecking a previously hinted route position is free; When device storage is available, Undo, Restart and refresh do not refill hints. If saving is blocked, used hints last only for this visit. A head with no legal forward move gets a general reminder after about three seconds, without a retreat count or marked recovery point.
Where is my progress saved?
Routes and completion are saved in this browser on this device when storage is available. If saving is blocked, the board shows a notice and you can keep playing. Each board has a separate run. Clearing site data removes that local progress; there is no account sync for this game.