Play Kakuro Pro Online: The Ultimate Math & Logic Puzzle

If you have already mastered our Daily Sudoku Challenges and are looking for a brand new way to test your brain, it is time to try Kakuro Pro.

Often described as a mathematical crossword puzzle, Kakuro (also known as Cross Sums) blends the deductive logic of Sudoku with simple addition. It is highly addictive, incredibly rewarding, and completely free to play right here in your browser.

Choose your difficulty below and start calculating!

How to Play Kakuro (Rules for Beginners)

If you are new to Kakuro, the board might look a little intimidating, but the rules are actually quite simple. Your goal is to fill all the empty white squares with numbers.

To win the game, you must follow these three golden rules:

1. Use 1 through 9: You can only put the numbers 1, 2, 3, 4, 5, 6, 7, 8, and 9 into the white squares. (Zero is never used).
2. Match the Clues: The black squares contain diagonal lines with numbers in them. These are your “clues.”
   • A clue in the top right means the numbers in the horizontal block next to it must add up to that exact sum.
   • A clue in the bottom left means the numbers in the vertical block below it must add up to that sum.
3. No Repeats allowed: You cannot repeat a number within a single continuous run. For example, to make the sum of 4 using two squares, you must use 1 and 3. You cannot use 2 and 2!

(To play the game above, simply tap an empty white square to select it, then use the on-screen number pad or your keyboard to fill in your guess. The row will light up red if you make a mistake, and green when you get the math perfectly right!)

Winning Strategies: How to Solve Kakuro Puzzles

Don’t just guess randomly! Kakuro is a game of pure logic. Here are two of the best strategies to help you conquer the Hard difficulty:

1. Memorize the “Magic Blocks” (Unique Sums)

Because you cannot repeat numbers, certain clues can only be solved with one specific combination of numbers. Memorizing these is the secret to playing fast. Always look for these first:

• Sum of 3 (in 2 squares): Must be 1 and 2.
• Sum of 4 (in 2 squares): Must be 1 and 3.
• Sum of 16 (in 2 squares): Must be 7 and 9.
• Sum of 17 (in 2 squares): Must be 8 and 9.
• Sum of 6 (in 3 squares): Must be 1, 2, and 3.

2. The Power of Intersections

If you have a horizontal clue of 16 (which must be 7 and 9) crossing a vertical clue of 4 (which must be 1 and 3), what number goes in the square where they cross? Since the vertical line can only use a 1 or a 3, the intersecting square cannot possibly be a 7 or a 9. You have to look for the numbers that satisfy both lines at the same time. Finding these forced intersections will break the board wide open.

What is Kakuro?

Originally appearing in American puzzle magazines in the 1960s under the name “Cross Sums,” the puzzle was later imported to Japan where it was renamed Kakuro. Today, it stands proudly alongside Sudoku, Hashiwokakero, and Nonograms as one of the most popular logic grid puzzles in the world.

Can you beat the Hard Mode?

Did you manage to clear the 9×9 board today without using the Solution button? Which clue tripped you up the most? Let us know your best times and strategies in the comments below!