Puzzle Week, Day 5: Masyu
I am sure most of you have not heard of Masyu. I encountered this puzzle when I purchased (or received as a gift) a book called something like "The Monster Book of Japanese Puzzles". Masyu became one of my favorites. It's not too difficult in my opinion, but very fun. The idea is that you have black and white circles in a grid. You have to draw one continuous line that goes through all the circles. Lines cannot pass over one grid cell more than once. Lines must also turn 90 degrees when encountering a black circle. When encountering a white circle, lines cannot turn on the circle, but must turn before or after (or both). That is all there is to it. A sample puzzle with solution looks like this:
Interestingly, the name Masyu means "evil influence". That is not the original name though. The original name was actually Shiroshinju Kuroshinju, which means "white pearls and black pearls" in Japanese. Some of the characters were misread by the preseident of Nikoli, the company who publishes these puzzles, and the name became Masyu. Personally I prefer the short and simple Masyu.
Masyu books are not very common, but I have seen them in stores, as individual books and as part of puzzle collections. If you are really eager to try Masyu and can't find it, you can check the Nikoli website and order a book directly from Japan. Enjoy!