In short: Sudoku is a placement puzzle — fill digits so each appears once per row, column and box. Masyu is a path puzzle — draw one loop that obeys pearl rules. Both have a unique solution reachable by logic, and both were popularised by the Japanese publisher Nikoli.
Side by side
| Masyu | Sudoku | |
|---|---|---|
| Type | Path / loop puzzle | Number placement puzzle |
| Grid | Any size, commonly 6×6 to 25×25 | Usually 9×9 with 3×3 boxes |
| Clues | White and black pearls | Given digits |
| Symbols needed | None — just a line | Digits 1–9 (as symbols; no arithmetic) |
| Core logic | Shapes, connectivity, avoiding small loops | Elimination: where can each digit go? |
| Global rule | Exactly one loop | Each digit once per row, column and box |
| Nikoli connection | Developed in Puzzle Communication Nikoli | Named and popularised by Nikoli |
A shared publisher
Modern Sudoku descends from “Number Place”, published by Dell Magazines in the late 1970s and credited to Howard Garns. Nikoli introduced it in Japan in the 1980s and gave it the name Sudoku before it became a worldwide craze in the 2000s. Masyu, by contrast, was developed inside Nikoli’s own magazine — see the history of Masyu.
How the thinking differs
Sudoku: candidates and elimination
Sudoku solvers track which digits are still possible in each cell and remove candidates using rows, columns and boxes. Most reasoning is about sets of possibilities.
Masyu: shape and connection
Masyu solvers reason about how a path can bend. Each edge is simply “line” or “no line”, but whether a line is possible depends on pearls, neighbouring lines and the requirement that everything joins into one loop. The no-premature-loop rule has no real Sudoku equivalent — it’s a global, topological constraint.
What transfers
- Discipline. Only write what you can prove.
- Scanning routines. Sudoku solvers already work in systematic sweeps; Masyu rewards the same habit (a five-step routine).
- Contradiction chains. Advanced Sudoku techniques test an assumption and look for a contradiction — exactly the what-if method used on Hard Masyu.
Which is harder?
Neither, in general — difficulty depends on the individual puzzle. Many Sudoku players find Masyu’s first puzzles quick to learn because there are only three rules, and enjoy that grid size can scale from a two-minute 6×6 to an hour-long 25×25.
Try Masyu as a Sudoku player
- Read the three rules — it takes two minutes.
- Play an Easy Masyu, then a 10×10 Medium.
- Make it a habit with the Daily Masyu.