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Slitherlink

Draw a single loop using logic alone

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You completed the loop perfectly

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What Is Slitherlink?

Slitherlink is a logic puzzle played on a grid of dots. Your goal is to connect adjacent dots with line segments to form a single closed loop. Some cells contain numbers from 0 to 3, telling you exactly how many of the cell's four edges are part of the loop. The challenge is to satisfy every number constraint while creating one unbroken path with no branches or dead ends.

How It Works

Click or tap between two adjacent dots to draw a line segment. Right-click or long-press to mark an edge with an X (meaning it's definitely not part of the loop). Use the numbers as clues: a 0 means none of that cell's edges are used; a 3 means three of four edges are drawn. Start with the easiest deductions — cells with 0 or 3 — and work outward using logic.

Frequently Asked Questions

What do the numbers mean?

Each number tells you how many of the four edges surrounding that cell are part of the loop. A cell with 3 has three drawn edges and one gap. A cell with 0 has no edges drawn around it at all. Empty cells can have any number of edges.

Is the solution always unique?

Yes! Every puzzle generated here has exactly one valid solution. The clue numbers are carefully calibrated so that logical deduction leads to a single answer without ambiguity.

Do I need to guess?

No. Every Slitherlink puzzle can be solved through pure logic. If you feel stuck, look for cells with 0 or 3, check corners and edges of the grid, and look for places where constraints from neighboring cells overlap.

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Slitherlink was invented by Nikoli in 1989 and is considered one of the most elegant logic puzzle types ever created.

Last updated: April 2026

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