Slitherlink: The Number-Loop Puzzle Similar to Sudoku

The puzzle you're describing is Slitherlink (also called Fences, Loop the Loop, or Dotty Dilemma).

How to Play

1. Grid: Typically 10×10 dots forming 9×9 cells (sizes vary).
2. Clues: Numbers 0–3 inside some cells indicate how many of that cell's four sides are part of the loop.
3. Goal: Draw a single, continuous, non-intersecting loop along grid lines connecting dots.
4. Rules:
   • Loop lines run horizontally/vertically between adjacent dots.
   • No branches, dead ends, or crossings.
   • Each numbered cell must have exactly that many sides used by the loop.

Example Logic

• A 0 means no lines on any side—mark all four edges with X.
• A 3 means three sides are lines—only one edge is empty.
• Adjacent 3s force specific patterns; 0s and 3s are powerful starting points.

Where to Play

• Web: puzzle-slitherlink.com, Simon Tatham's Portable Puzzle Collection
• Apps: "Slitherlink" by Conceptis, "Logic Puzzles" by Egghead Games.
• Print: Nikoli magazines, puzzle books.

Want a beginner 5×5 to try? I can generate one.