Masyu
Also Known As:
Pearl Necklace, Shinju, Shinju no Kubikazari
This path puzzle is another Nikoli creation, notable for the absence of numbers.
Maki Kaji, President of Nikoli, has said: 'the secret of a good puzzle is to make the rules simple for everyone, including beginners.'
Masyu is a good puzzle, but the rules are a little challenging to follow. Once the solver gets to grips with the significance of the circles, things fall into place.
Instructions
Draw a complete loop which passes through all cells containing a circle. The loop can travel vertically or horizontally. It must not cross itself, branch off, or pass through the same cell twice.
When passing through a cell containing a white circle, the loop must go straight through the cell and turn 90 degrees in the previous and/or next cell. When passing through black circles, the loop must turn 90 degrees in the same cell as the circle and pass straight through the directly adjacent cells on either side.
Related Puzzles
Loop-The-Loop Nurikabe