How to Play Kakuro: Interactive Lesson

Kakuro is a number puzzle that looks like a crossword with sums instead of words. This free lesson teaches you how to play kakuro with a live grid you can click and type into. It takes a few minutes, needs no sign-up, and runs entirely in your browser, so nothing you type is sent anywhere.

You start by reading the clues, then learn the two rules and watch a real puzzle get solved one square at a time. Each step explains why a digit is forced, so you learn a method rather than a trick. In the last step you solve a 6x6 puzzle yourself, with a Hint button that gives the reason, not just the answer.

When you finish, you can play kakuro online on the size you like, or print puzzles to solve with a pencil.

How to use the kakuro lesson

1. Pick a step on the left, or press Next step at the bottom of the lesson to move on.
2. Read the grid: click a clue square or a white square and the lesson highlights the run it belongs to.
3. The two rules: type digits 1 to 9 into the small grid. The list beside it shows, for each run, how close you are to its sum and whether a digit repeats.
4. Sums with one answer: choose the number of squares and the sum to see every way to make it. The quick examples show sums that can be made only one way.
5. Watch a puzzle solved: press Fill next square to fill one square at a time, with the reason shown under the grid. Undo square takes one back and Start again clears the grid.
6. Your turn: click a white square and type a digit, or use the number pad. Hint highlights a square the sums force and says why. Check marks wrong digits.

On a phone, tap a square and use the number pad. On a computer, type digits straight into the selected square, use the arrow keys to move between white squares, and press Backspace, Delete or 0 to clear a digit. Nothing needs installing, and you can repeat any step as often as you like.

How to play kakuro: what are the rules?

Kakuro is played on a grid of white squares and black clue squares. You fill every white square with a digit from 1 to 9. A run is a line of white squares going across or down. The clue in the black square before a run gives its sum: a number in the top right is for the run to its right, and a number in the bottom left is for the run below.

There are two rules. First, the digits in a run must add up to its clue. Second, a digit cannot repeat inside the same run. The same digit can appear again in a different run, because only the squares of one run have to differ.

Every white square belongs to two runs, one across and one down, so each digit has to satisfy both clues. That crossing is what makes the puzzle solvable.

How do you solve kakuro?

Most solving uses the same few moves, and the lesson shows each one:

1. Start with runs that have only one possible set of digits. Two squares that add up to 3 must be 1 and 2, and 4 must be 1 and 3. Likewise 16 is 7 and 9, and 17 is 8 and 9. In three squares, 6 is 1, 2 and 3, and 24 is 7, 8 and 9. A run of nine squares with the sum 45 uses every digit once.
2. For each empty square, list the digits its across run allows and the digits its down run allows. If only one digit is on both lists, write it in.
3. When a run has one empty square left, that square is the clue minus the digits already in the run.
4. Every time you place a digit, remove it from the other squares of its two runs.

Do not guess at the start. A sum such as 10 in two squares has four ways (1 and 9, 2 and 8, 3 and 7, or 4 and 6), so leave it until a crossing run narrows it down.

Frequently asked questions

How do you play kakuro in one sentence?

Fill every white square with a digit from 1 to 9 so that each run adds up to its clue, using no digit twice in the same run.

Can a digit repeat in kakuro?

Not inside one run. Within a single across or down run every digit must be different, but the same digit can appear again in another run of the grid.

Do you ever have to guess in kakuro?

Not on the Easy puzzles on this site, which can be solved using sum combinations and the overlap of each square’s two runs. Medium puzzles also need reasoning about a whole run. Hard puzzles need at least one step of trial and error.

Is the lesson free, and is anything saved?

Yes, it is free with no sign-up. The grids and your digits stay in your browser, and nothing is uploaded. Nothing is saved either, so a reload starts the lesson again at the step in the address.

Where should a beginner start after the lesson?

Start with a Mini 6x6 puzzle on the Easy setting. You can play kakuro online on that size or print an easy mini kakuro and solve it with a pencil.

Related tools

• Play kakuro online: use it when you are ready to solve a full puzzle with notes and hints.
• Printable kakuro generator: use it when you want puzzles on paper, with answer pages.
• Kakuro cheat sheet: use it when you need the digit combinations for a sum.
• Kakuro solver: use it when you are stuck on a puzzle from a magazine or a book.
• Easy mini kakuro to print: use it for a first kakuro on a small 6x6 grid.
• Number crossword generator: use it when you want another number puzzle with similar logic.