Daily Kakuro
The rule
Fill the white squares with 1 to 9 so each run adds up to the number before it. No digit repeats inside a run.
A shaded square split by a diagonal carries two numbers. The one above the line is for the run going across to its right, the one below is for the run going down.
Tap a square, then tap or type a digit. A run that breaks a rule turns red.
Where to start
Look for the runs whose total can only be made one way. Two squares adding to 3 must be 1 and 2, and to 17 must be 8 and 9. Three squares adding to 6 are 1, 2 and 3, and to 24 are 7, 8 and 9. Those are the footholds, and every grid here has some.
Then work the crossings. A square sits in an across run and a down run at once, so a digit has to satisfy both, and that is usually what settles it.
In your hands
If you like a puzzle that is all arithmetic and no luck, the mechanical puzzles are the same pleasure in wood and steel.
Why Every Grid Has Exactly One Answer
Kakuro has a quiet trap in it. Any two by two block of white squares can be shifted, adding one to the squares on one diagonal and taking one off the other, and every single run total stays the same. A grid that allows that has two answers, not one, and no amount of careful reasoning will choose between them.
You cannot avoid such blocks. The topmost, leftmost white square on any board has to pair rightwards and downwards, and the square to its right has to pair downwards too, so a two by two is forced. What stops the shift is the digits: it only works if the shifted numbers stay between 1 and 9 and still never repeat inside a run. Every grid here had its digits adjusted until no shift survives anywhere, and was then checked by counting its answers. Each one has exactly one, and a solver using no guesswork can reach it.
More to Play
There are twenty four daily sudoku variants, a slitherlink, a shikaku, a fillomino and a pentomino board. For puzzles you can hold, see mechanical puzzles.
Small enough to live on a desk and be picked up whenever a few minutes go spare. See the 3 Piece Cross, or the rest of the collection.
Frequently Asked Questions
How do you play Kakuro?
Fill the white squares with 1 to 9 so each run adds up to the number before it. No digit repeats inside a run.
Is Kakuro free to play?
Yes. There is a new kakuro here every day, free, with no account and nothing to install. It plays in the browser on a phone or a computer, and it remembers where you got to.
Can every puzzle be solved?
Yes. Each grid is checked twice over: counted to prove the sums admit only one answer, then handed to a solver using forced moves alone.