Daily logic puzzle
Kakuro online, a new wood every midnight.
Kakuro is a crossword made of sums: every run of cells adds up to the number in its clue, the digits 1 to 9 are used and none repeats inside a run. Ours is called Squirrels, it is free, there is no account and no advertising, and a new one appears at midnight.
- a new grid at midnight, easy on Monday and twelve by twelve on Sunday
- exactly one solution, reachable by reasoning, checked by program
- hints that explain the technique, a two step Check, no red ink while you play
Today's wood. Each sign says how many acorns are in the run that follows it.
The rules
Three rules, and that is the whole game.
Kakuro is also published as Cross Sums and Kakkuro. The rules are the same under every name.
- Squirrels hide acorns in the hollows. Each sign tells how many acorns are in the run of hollows to its right or below it. A run is the unbroken line of hollows that follows a sign and ends at the next trunk or at the edge of the wood.
- Every hollow holds 1 to 9 acorns, and no number repeats within a run. Every hollow belongs to one run across and one run down at the same time, so the number you write has to suit both.
- Exactly one filling fits every sign.
Our name for it
We call it Squirrels.
The puzzle is known as Kakuro, from the Japanese for addition cross. We call ours Squirrels because the cells are hollows with acorns in them and the clues are what the squirrels counted, and because it makes the one rule people forget, that no number repeats inside a run, sound like something a squirrel would care about.
The rules are untouched. The usual arithmetic applies: a run of two adding to seventeen is eight and nine, a run of three adding to six is one, two and three, and those forced combinations are where almost every grid opens.
Where to start
Three ways in.
The archive of past grids is free as well and goes back a year: Squirrels archive.
- Play today's wood
The daily puzzle, easy on Monday and twelve by twelve on Sunday, new at midnight.
- How to play Kakuro
The rules with a worked example, the controls and the forced sums worth memorising.
- Practice sets
Sets by difficulty when one grid a day is not enough.
One solution
A program says so, not a person.
Every puzzle we publish has exactly one solution, and it is a program that decides. The generator throws a candidate away unless the solver returns exactly one solution and unless a second solver, restricted to human style reasoning, finishes it without guessing.
You can see the check yourself: the file tests.mjs in the game folder runs it over thirty days in every size. It matters here because a Kakuro grid can have several fillings that satisfy every clue if the constructor is careless, and then the printed answer is only one of them.
While you play, nothing goes red. A mistake is shown only by Check, in two steps: first how many cells are wrong and roughly where, then which ones. Corner and centre pencil marks are built in, so you can note the candidate sets as you go.
Questions
Questions about Kakuro.
What is Kakuro?
A crossword where the answers are numbers. Each clue sits in a divided cell and gives the sum of the unbroken run of cells to its right or below it. You fill the run with the digits 1 to 9 so that they add up to the clue and no digit appears twice in the same run. Every cell belongs to one across run and one down run at once.
Is it free here?
Yes. The daily puzzle, the practice sets, the archive going back a year, the hints and the Check are all free, with no account and no advertising. We sell printable puzzle books on the same site, and that is the whole business model.
Can a digit repeat inside a run?
No, never within the same run. It may of course appear again in a different run, including one that crosses it. That single rule is what turns the sums into logic rather than arithmetic, because it makes short runs with extreme totals completely forced.
Is there a zero?
No. Only the digits 1 to 9 are used, so the shortest possible run of two has a minimum of three and a maximum of seventeen. Knowing those limits is half the technique.
Do I ever have to guess?
No, and that is checked rather than promised. Every published puzzle was solved by a program restricted to reasoning before it was allowed out. If you are stuck, Hint names the technique and the run before it fills a cell.
Where can I get more of these on paper?
In the Squirrels book: one hundred Kakuro puzzles as a printable PDF in A4 and US Letter, with the solutions at the back. There is a free five puzzle sample to look at first. See the <a href="/puzzle-books/kakuro-puzzle-book/">Kakuro puzzle book</a>.
Related
More of the same.
One hundred of these on paper, with the solutions at the back: Kakuro puzzle book (PDF, free sample).
All ten daily games are on one page: daily logic games.
Auf Deutsch: Kakuro online spielen.