Shikaku is another original Nikoli puzzle, which provides a special sense of solving while complying with a very simple rule. Beginners may try starting with a guess, but will quickly see that the fun is searching for rectangles by logic.
Shikaku is also a great math trainer for kids. While playing the game they learn multiplication such as a 12 can be 1×12, 2×6 or 3×4. And if you get stuck, look at the puzzle from a distance and you will soon find the next rectangle.
Hints & Tips
Try to find the numbers where you can draw the shape quickly. For example, in the partially complete puzzle, number 5 and number 8 you can solve quickly. Number 6 has many possibilities that can be solved later on.
One unit comes with 30 puzzles with 60 pieces of paper (Two sheets of paper per puzzle so that you can enjoy it twice!).
Go to the official Nikoli website for rules of Shikaku
Interview with the Inventor of Shikaku, Yoshi Anpuku
Q: How did you come up with Shikaku?
Yoshi: I wanted to create a puzzle with simple rules — something that could help children become familiar with numbers and easy multiplication. Learning multiplication is much easier for children if it’s fun.
Q: When did you invent it & how long did it take to complete?
Yoshi: It was 30 years ago when I was a college student in Kyoto. I was inspired by a type of puzzle in which you put pieces together to make certain shapes. The Haberdasher’s Puzzle, invented by English author and mathematician Henry Dudeney, cuts an equilateral triangle into four pieces that can be rearranged to make a square. In Japan there are similar puzzles that require you to put pieces of paper together. I thought, “There must be something we can do to replicate this puzzle with only a pencil and paper.” Instead of cutting paper, I thought, “Maybe I can divide cells.” I was on a train one day and it came to me how to construct the parameters of the puzzle. It took me about two or three months from the conception to the final puzzle.