Like Sudoku, Futoshiki enormous popularity in Japan can be explained by its deceptive simplicity. Futoshiki (the name literally means “not equal”) is based on a simple grid into which, like the more famous puzzle, numbers are inserted according to a few simple rules.
The numbers one to four must be placed in each row and each column, without any repeats; “greater than” or “less than” signs – literally, “not equal” to – between boxes are the only tips to guide you. You can also buy Futoshiki Puzzle Books at Amazon.com. Happy Puzzling!