Puzzle guide

How to solve Masyu

Masyu has no numbers at all, only pearls. You draw one loop, like a necklace, that passes through every pearl, and each colour of pearl tells the loop how to move. Once you know a few pearl patterns, the loop almost draws itself.

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The rules

Draw one closed loop through the cells. It never crosses itself or splits, and it passes through every pearl.
A white pearl: the loop runs straight through it, and turns in at least one of the two cells next to it.
A black pearl: the loop turns at it, and runs straight for at least one cell on both sides.
The loop does not have to visit every cell.

A solved puzzle

A solved puzzle. The loop turns at each black pearl and goes straight through each white one, turning just before or just after it.

Your first moves

Find pearls on the edge of the board. A white pearl there must run along the edge.
Find black pearls in or near a corner. They usually give you two straight lines at once.
Look for two black pearls side by side and three white pearls in a row: both are patterns with a fixed answer.
Put an X on every gap the loop cannot use, and keep extending your lines from the pearls.

Techniques, step by step

A white pearl on the edge

A white pearl runs straight through. On the top row it cannot go up and down, because there is no cell above it. So it runs along the edge, from its left neighbour to its right neighbour. The same is true for any white pearl against a border.

On the edge, the white pearl can only run sideways.

A black pearl in a corner

A black pearl turns, and then goes straight for at least one more cell in both directions. In the corner it can only turn one way: right and down. So the loop leaves it in two straight lines of two segments each. A black pearl one cell away from an edge works the same: it cannot go towards that edge, because there would be no room to go straight.

The corner pearl turns, and both arms run straight for two segments.

Straight through a white pearl

A white pearl goes straight: either left and right, or up and down. Here the gap to its right already has an X, so it cannot go sideways. That leaves up and down. Each time one side of a white pearl is blocked, you know its whole line.

Sideways is blocked, so the white pearl runs up and down.

Two black pearls side by side

Two black pearls stand next to each other. If the loop used the gap between them, one pearl would have to turn there while the other needs a straight cell, and that cannot work for both. So the gap between them gets an X, and each pearl leaves away from the other.

The loop never runs between two black pearls side by side.

Three white pearls in a row

If the loop ran along three white pearls in a row, the middle one would have no turn next to it, because its neighbours would also go straight. So the loop crosses all three the other way: each pearl gets a straight line across the row.

Three whites in a row: the loop crosses each of them.

Do not close the loop too early

There is only one loop, and it must reach every pearl. Joining these two line ends would close a small loop while a pearl is still outside it. So that gap gets an X. On harder boards, also check that the two ends of every line you have drawn can still reach each other.

Closing this gap would shut out the pearl, so it gets an X.

Common mistakes

A white pearl without a turn. The loop must turn in the cell just before or just after a white pearl. A long straight line through it is not enough.
A black pearl with a short arm. After turning, the loop goes straight for at least one more cell on both sides.
Two loops. All lines must join into one single loop that visits every pearl.
Trusting a full loop with no warnings. The app checks the pearl rules only when the board is judged as a whole, so look at every pearl before you finish.

Questions and answers

What is Masyu?

A Japanese logic puzzle where you draw one closed loop through every pearl on a grid. White pearls are passed straight through, black pearls are turned at.

Does the loop have to go through every cell?

No. It goes through every pearl, but empty cells can stay off the loop.

How do I draw the loop?

Drag from cell to cell to draw. Tap a segment between two cells to put an X on it, and tap again to clear it.

What is the difference between white and black pearls?

At a white pearl the loop goes straight and turns next to it. At a black pearl the loop turns and goes straight next to it. They are opposites.

Where should I start?

With pearls on the edges and in corners, then with black pearls side by side and white pearls three in a row. Those patterns fix lines before you have to think about the whole loop.

Ready to play?

Edges, corners, black pairs and white rows, and never a loop closed too early: that is how a Masyu necklace comes together, pearl by pearl.