What is a Masyu solver?
A Masyu solver is an online tool that completes a black and white pearl loop puzzle from the clues you enter. Masyu is a Japanese logic puzzle where the answer is one continuous closed loop that passes through every pearl.
This page is written for people searching for Masyu solver, Masyu puzzle solver, online Masyu solver, Masyu helper, Masyu answers, black pearl white pearl puzzle solver and loop puzzle solver. You can reveal the whole answer, check a partial loop or ask for one next logical move.
- Enter white pearls and black pearls on a custom grid.
- Mark known loop segments or crosses before solving.
- Solve a Masyu puzzle from a book, app, newspaper or printable sheet.
- Use Next move when you want a controlled hint instead of the full solution.
How to use this Masyu solver
Choose a grid size, then click cells to cycle between blank, white pearl and black pearl. Click between two neighbouring cells to cycle an edge through a line, a cross and blank.
Press Solve to fill a complete loop. Press Check to test whether the current pearls and marks can still lead to a valid Masyu answer. Press Next move to highlight one forced line or cross with a short explanation.
- Use white pearls for circles that the loop must pass straight through.
- Use black pearls for circles where the loop must turn.
- Use crosses for edges you already know cannot be part of the loop.
- Clear lines when you want to keep the pearls but remove your partial path.
- Load an example if you want to try the solver before entering your own puzzle.
Masyu rules used by the solver
The solver follows standard Masyu rules. The final answer must be a single loop through the centres of cells. The loop cannot cross itself, branch, split into two loops or leave an open end.
Every pearl must be used. A black pearl must be a turn, and the loop must go straight through the next cell on both sides of that turn. A white pearl must be passed through in a straight line, with a turn immediately before or immediately after it.
- Black pearl: turn on the pearl, then continue straight on both exits.
- White pearl: go straight through the pearl.
- White pearl: at least one adjacent cell on the loop must be a turn.
- Every used cell has exactly two loop segments.
- All loop segments must belong to one connected closed loop.
Next move logic and Masyu strategies
The Next move button first applies local Masyu logic. If a black pearl can only turn one way, the solver can force the two turning edges and the straight extensions. If a white pearl has only one possible straight direction, the opposite edges are forced.
The solver also uses loop degree logic. A cell with two lines blocks every other edge, while a cell with one line and only one open exit must use that exit. If those deductions are quiet, the helper compares valid completions and shows an edge that every solution agrees on.
- Black pearl direction: opposite edges are blocked, perpendicular exits may be forced.
- Black pearl extension: the cells after a black pearl must continue straight.
- White pearl direction: the loop goes straight through, not around the pearl.
- Degree logic: loop cells need two lines, not one or three.
- Forced edge: every valid completion makes the same line or cross.
Why a Masyu puzzle can be impossible or ambiguous
A Masyu puzzle becomes impossible when a pearl can no longer satisfy its rule, when a path creates a branch or dead end, or when the lines close a loop before every pearl is included.
A puzzle can also be ambiguous. That means more than one loop satisfies the same pearls. Published Masyu puzzles usually aim for one unique solution, but a copied or homemade grid can sometimes allow several valid answers.