Slitherlink Puzzles Online — Close the Loop 7+

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Slitherlink (also called Loop the Loop or Fences) is a classic Japanese logic puzzle: a grid of dots where you draw lines to build one closed loop, and the number in a cell tells exactly how many of its four sides belong to the loop.

Here the grid is a carved wooden board with brass dots: 120 puzzles in four chapters, from a 4×4 warm-up to a 7×7 master board. Every puzzle is machine-checked to have exactly one solution, so it always yields to reasoning, never to guessing.

No timer and no answer hints: the board only marks a real rule break — three lines meeting at a dot, or a number with too many lines. A number turns green the moment it has exactly the lines it needs.

How to play

Tap the gap between two dots to draw a line; tap again to put a cross meaning 'no line here', and once more to clear. The first puzzle is a voiced lesson right on the live board. When the loop closes correctly, it lights up gold.

Big Undo is always at hand; Restart asks first, so a board is never lost to a slip of the finger.

What your child learns

Every cell is a small counting claim to test: 'this 3 needs three sides — which one is missing?'. Children practise counting, edge-by-edge deduction and the discipline of following a chain of consequences: one placed line forces the next. It is proof-style thinking dressed as a drawing game.

The science behind the games

Every Dad4Kids game is built on one simple truth: children want to play, not study — so we turn learning into a game worth replaying. The method draws on peer-reviewed research in game-based learning, motivation, and how memory works.

FAQ

What are the rules of slitherlink?

Draw one single closed loop along the grid lines. A numbered cell must have exactly that many of its sides in the loop; empty cells may have any number. The loop never crosses or branches.

Does the game show the answer?

No. The board marks only broken rules — a dot where three lines meet or a number with too many lines around it. Whether the loop is right you find out by closing it.

What age is it for?

The 4×4 chapter with a voiced lesson suits a seven-year-old; 6×6 and 7×7 boards are a genuine challenge for older kids and adults.

Is every puzzle solvable?

Yes: all 120 puzzles were verified by a solver to have exactly one solution.