The main difference: in Masyu the loop runs through cell centres and the clues are pearls that dictate the loop’s shape. In Slitherlink the loop runs along the grid lines between dots, and number clues say how many of a cell’s four sides the loop uses.
Side by side
| Masyu | Slitherlink | |
|---|---|---|
| Goal | One closed loop | One closed loop |
| Where the loop runs | Through cell centres | Along grid lines, dot to dot |
| Clues | White and black pearls | Numbers 0–3 inside cells |
| What a clue tells you | The loop’s shape at that cell | How many sides of that cell are on the loop |
| Must every clue be on the loop? | Yes — the loop visits every pearl | No — a 0 means the loop avoids that cell’s sides entirely |
| Typical feel | Visual, geometric, pattern-driven | Counting-driven, corner-heavy |
| Complexity (general case) | NP-complete | NP-complete |
What they share
Every global loop technique works in both puzzles:
- Degree rule. In Masyu each cell has 0 or 2 lines; in Slitherlink each dot has 0 or 2. Dead ends and forced continuations work identically (loop logic).
- No premature loops. Closing a smaller loop is always wrong unless it finishes the puzzle.
- Parity. A closed loop crosses any boundary an even number of times (parity in Masyu). In Slitherlink this “inside/outside” reasoning is especially important.
- Marking ✕. Recording impossible segments is half the work in both.
How solving differs
Masyu: reasoning about shapes
Masyu clues are local shape rules — “turn here”, “go straight here”. Progress comes from recognising pearl patterns such as adjacent black pearls or rows of white pearls. Because the loop must visit every pearl, pearls also act as “must-visit” anchors.
Slitherlink: reasoning about counts
Slitherlink clues are counts. Openings come from numeric patterns: a 0 removes four segments at once, and certain combinations — such as two 3s side by side — force several lines. The numbers interact with corners of the grid in ways that have no direct Masyu equivalent.
Which should you play first?
- Choose Masyu if you prefer visual puzzles, want the gentlest introduction to loop logic, or are teaching children — there are only two clue types and no numbers.
- Choose Slitherlink if you enjoy counting logic and dense, number-rich grids.
- Play both if you can: the loop skills from each make you noticeably better at the other.
Start with Masyu here: how to play, then try a 6×6 puzzle. For a broader comparison including Yajilin and Country Road, see Masyu vs. other loop puzzles.