Kakuro: Crosswords Meets Numbers

Kakuro is often called "crosswords with numbers." Like a crossword, the grid has white and black cells; like Sudoku, you fill cells with digits 1–9. In Kakuro, each "word" (a run of white cells) has a target sum, and you must fill the cells with unique digits that add up to that sum. No digit repeats within the same word. The mix of logic and arithmetic makes Kakuro a natural next step for Sudoku fans who want a new challenge.

Kakuro trains the same logical elimination skills as Sudoku, plus mental arithmetic. You often work out which digit combinations are possible for a given sum and length, then eliminate options until only one remains. It is a great way to keep the brain engaged with a different structure.

KenKen and Other Variants

KenKen is a grid puzzle where each "cage" (a group of cells) has a target number and an operation (add, subtract, multiply, or divide). You fill the cage with digits that satisfy the target using that operation; digits usually cannot repeat within a row or column. KenKen combines logic with basic arithmetic and is available in many sizes and difficulty levels.

• Kakuro: digit sums, no repeats in a "word."
• KenKen: cages with targets and operations.
• Variants: 6×6 Sudoku, Samurai Sudoku, and more.

Why Try Other Number Puzzles?

Exploring puzzles beyond Sudoku can keep your routine fresh and challenge different parts of the brain. Kakuro and KenKen use similar logical elimination but add arithmetic and different grid structures. That variety can prevent boredom and support long-term motivation. Many online puzzle sites offer a mix of types, so you can switch between Sudoku and other number puzzles depending on your mood.

For the story of Sudoku and its cousins, read the history of Sudoku. For how logic puzzles train the brain, see how logic puzzles train your brain. For the shift to online play, check the rise of online puzzle games.