Does the loop have to visit every square?

No. It only has to pass through every pearl. Empty squares can stay empty.

What’s the difference between white and black pearls?

At a white pearl the loop goes straight, and turns in the square before or after it. At a black pearl the loop turns, and goes straight through the next square on both sides.

Does every Masyu have one solution?

Yes. Each one is checked by a solver that counts every possible answer, and solved step by step without guessing before it’s published.

How big are the puzzles?

The daily Masyu is 8×8. Practice puzzles come in 6×6, 7×7 and 8×8.

How to play Masyu (Pearl): rules, tips and FAQ

The rules

Draw one loop through the centres of the squares, moving across and down. It never crosses or branches, and it passes through every circle.

At a white circle the loop goes straight, and it turns in the square just before or after the circle (or both).

At a black circle the loop turns, and it goes straight through the next square on both sides.

Watch one get solved

DemoStep through a small Masyu being solved. Each move follows from one rule, and the ring shows which clue it comes from.A black pearl turns, then goes straight through the next square on both sides. In the top-left corner the only way to turn is right and down, two squares each way.Same for the black pearl in the bottom-right corner: left and up, two squares each.A white pearl goes straight through. The line already enters the top white pearl from the left, so it carries on to the right.Likewise the bottom white pearl: in from the right, straight out to the left.Now follow the loose ends. Each one is in a corner and can only turn, which closes the loop. Solved!

Using the board

Drag from square to square to draw the loop. Drag back over a line to erase it.

Tap right on the border between two squares to add or remove that one piece of line.

A pearl turns red when the lines around it break its rule: a turn on a white pearl, or a black pearl gone straight.

Lines turn red where three meet, or where a closed loop leaves pearls or other lines out.

What is Masyu?

Masyu is a loop puzzle. You draw one closed loop through the centres of the squares, and it has to pass through every pearl. White pearls make the loop go straight through them, with a turn just before or just after. Black pearls make it turn, and then go straight for two squares in both directions.

Nikoli introduced it around 2000. The name is a playful misreading of mashinju, Japanese for “pearl”, which is why it’s also called Pearl.

How to start a Masyu

Start at the edges. A black pearl next to the edge can’t send its loop towards the edge, so it goes the other way for two squares. A white pearl on the edge must run along the edge.

Then look for patterns: three white pearls in a row all run across the row, and two black pearls side by side each head away from the other.

From there, follow loose ends. A line that can only continue one way has to go that way, and any line that would close a small loop before all the pearls are in is ruled out.

Questions

Does the loop have to visit every square?: No. It only has to pass through every pearl. Empty squares can stay empty.
What’s the difference between white and black pearls?: At a white pearl the loop goes straight, and turns in the square before or after it. At a black pearl the loop turns, and goes straight through the next square on both sides.
Does every Masyu have one solution?: Yes. Each one is checked by a solver that counts every possible answer, and solved step by step without guessing before it’s published.
How big are the puzzles?: The daily Masyu is 8×8. Practice puzzles come in 6×6, 7×7 and 8×8.

Play today’s Masyu Solving techniques