On the Subject of Mastering Masyu

Just some dots and lines, really.

Masyu is a simple, aesthetic logic puzzle played on a grid. Each puzzle contains black and white dots. The objective is to create a single loop that passes through every dot, abiding by the following two rules:

  • The loop must turn in a black dot, and it must pass straight through both of the following cells on each end.
  • The loop must pass straight through a white dot, and it must turn in either one or both of the following cells on each end.

Using these two rules and some logic, the puzzle's unique solution can be found.

To form the loop, click on a segment in the grid. The loop cannot go outside of the grid, so the segments around the edge of the grid cannot be clicked. To remove a created line, click on it a second time. Right-click to cycle a square between empty, white circle then black circle.

Once the final loop is complete, click the black button to submit the solution. If it is incorrect, a strike will be registered, but the module will not reset.

To start over, press and hold the white button until all of the lines clear. The circles will not change, i.e. it is still the same puzzle.


Here are some tips and suggestions, for those who are new to this puzzle:

  • Avoid guesswork; only place lines when you know that they are correct.
  • When stuck, look back at the circles in the puzzle; you should be able to complete many of them using the two rules.
  • Since the loop cannot go outside of the grid, circles on the edges of the grid are easiest to solve.
  • All ends must connect to other ends; avoid trapping an end on its own!
  • Use negations; if forming a line would break a rule, it usually guarantees that another line should be formed instead. For example, if a black circle cannot have a line heading north, then it must have a line heading south.
  • Refer to the chart on the next page for visual examples of the rules: