Shikaku blog

Names, math, history, and guides for Shikaku fans. New here? Start with the puzzle's many names, then explore the rest. Prefer to just play? Jump in below.

• Shikaku, Cellblocks & Rectangles: A Puzzle With Many Names

  Cellblocks, Rectangles, Divide by Box and Shikaku are all the same puzzle. Here's why this Nikoli puzzle has so many names, which name is used where, and how to recognise it.

• Shikaku for Math: How a Puzzle Teaches Multiplication & Factoring

  Shikaku is a brilliant math puzzle for kids and adults. Every clue is a factoring problem, so playing it builds multiplication, factor pairs and area skills. Here's how, and how to use it for learning.

• The History of Shikaku: Nikoli's \"Cut Into Squares\" Puzzle

  The history of Shikaku: how a Kyoto student invented this rectangle-dividing puzzle in 1989, what its Japanese name means, and how Nikoli turned it into a worldwide classic.

• What Makes a Shikaku Puzzle Hard?

  What makes a Shikaku puzzle hard? Grid size, big numbers with many factorisations, and competing rectangles all play a part. Here's what separates an easy grid from a brutal one.

• Puzzles Like Shikaku: Grid-Division Logic Puzzles

  Love Shikaku and want more? Here are puzzles like Shikaku — grid-division and region logic puzzles from Fillomino to Suguru and KenKen — and what makes each a great next challenge.

• Shikaku Variants: Beyond the Classic Rectangle Puzzle

  Shikaku has a family of variants that twist the classic rectangle puzzle — toroidal grids, two-number rectangles, pentomino regions and more. Here's a tour of the main Shikaku variations.

• Is Shikaku Like Sudoku? Why It's a Rectangle Puzzle, Not a Number Puzzle

  Is Shikaku like Sudoku? They share a numbered grid, but they play nothing alike — in Shikaku you draw rectangles, you don't place numbers. Here's how the two puzzles really compare.