easy
5×5 and 6×6 grids. A gentle introduction to loop logic.
0 of 25 free easy Number Loop puzzles used
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Number Loop
Pick your Number Loop challenge
Draw a single closed loop along the grid edges so every numbered cell is surrounded by exactly that many loop edges. Three difficulties scale from cosy 5×5 grids up to sprawling 10×10 boards.
Today's editions
Pick a difficulty
medium
7×7 and 8×8 grids. Longer loops to plan around.
0 of 25 free medium Number Loop puzzles used
hard
10×10 grids. Big boards that take real planning.
0 of 25 free hard Number Loop puzzles used
From the rulebook
How to play Number Loop
Number Loop, known to many puzzlers as Slitherlink, asks you to draw one single closed loop along the edges of the grid. Each numbered cell tells you exactly how many of its four sides the loop uses; cells without numbers can be bordered by any count. The loop never crosses or branches.
Zeros are the strongest clues. No loop edge touches them, so mark all four sides off. A 3 next to a 0, or two 3s side by side, force edges immediately; corners constrain their numbers too. From there it's about propagation: every edge you rule in or out cascades through neighbouring cells, and the single-loop rule itself eliminates stray closed circuits before the grid is full.