One Line Puzzle Strategy: Visit Every Cell in Order
One Line grows from 5×5 to 8×8 boards with five to eight checkpoints. Start at 1, visit the numbers in order, and enter the final number only when every other cell has been visited. Walls block movement between adjacent cells. You can tap, drag or use arrow keys.
Play Game
Check corners and trapped regions first
A corner of a 5×5 board has only two neighbors. Unless that corner is the start or finish, your line must enter through one neighbor and leave through the other. Using both neighbors too early can isolate the corner.
A line that separates the remaining empty cells into disconnected regions cannot visit both without crossing itself. Before choosing a move, check that the unvisited area stays connected. Visiting 3 before 2, or reaching the final checkpoint before filling the board, is rejected.
Tap an earlier visited cell or use Undo to rewind. A hint rewinds any section that differs from a prepared solution and reveals the next cell on that solution. Each hint costs 100 points and each move costs three points from a starting completion score of 1,000.
Finish at the final checkpoint
Start at 1, visit each number in order, and finish at the final checkpoint after filling every cell. Entering it early is blocked. You cannot move across the dark walls between cells. A short route to the next checkpoint may leave too many cells behind, so plan the surrounding area as well as the next number.
Avoid isolated cells
A line can split the remaining empty area into disconnected pieces. Inspect corners and narrow exits before extending it. Fill a pocket of cells while preserving a route back out. You cannot cross your own line or move diagonally.
Use the input that suits you
Drag continuously, tap adjacent cells, or use arrow keys. Backspace rewinds one cell. Selecting any earlier cell in the current path rewinds to that point. These controls make it easy to compare routes without restarting the entire board.
Hints show a valid continuation
A hint reveals the next step on a known valid path. If your route differs, conflicting steps are rewound first. Each hint reduces the score by 100, with a minimum final score of one. Shared results include your score and challenge link but never the solution, so a friend can solve the same puzzle independently.