About Us
About kakurogame.app
We publish a free, modern browser version of Kakuro — the number crossword — with fresh puzzles that each have exactly one solution, and a layout that works on any screen.
Our craft
Sums that only fit one way.
Read the clue, narrow the digits, let the crossing runs decide. That loop is everything we design around.
- Digits per cell
- 1–9
- Grid sizes
- 3
- Solution per puzzle
- 1
Digits per cell
Grid sizes
Solution per puzzle
What we make
A free Kakuro that stays in the browser
kakurogame.app is the site behind our version of Kakuro. The product is a single-player logic puzzle: fill white cells with digits 1 to 9 so every run adds up to the clue that starts it, without repeating a digit inside a run. Each cell belongs to an across run and a down run, so each digit has to satisfy two sums at once.
There is nothing to download; the game is the website. That keeps load times short, works on phones and desktops alike, and avoids an account wall. Progress is kept in local browser storage on your device.
We are an independent site. If you are comparing us to another Kakuro site, this page speaks only for kakurogame.app. The rules and controls described in our how-to-play guide and FAQ describe this exact game.
Origins
Where Kakuro comes from
Cross sums
Kakuro belongs to a family of arithmetic crosswords. Puzzles of this kind appeared in American puzzle magazines in the mid twentieth century under names such as "Cross Sums", and are commonly credited to the designer Jacob E. Funk. The idea is simple to state: a crossword grid where the entries are digits and the clues are totals.
The name and the boom
The name Kakuro is a contraction of the Japanese kasan kurosu — "addition cross". Japanese puzzle publishers popularised the form from the 1980s, and it spread worldwide in the 2000s alongside Sudoku, becoming a staple of newspaper puzzle pages and puzzle apps.
This build
kakurogame.app is an independent, modern implementation of the standard rules. What is new is how it is delivered: puzzles generated on demand in your browser, each verified to have one solution, with a board that stays readable on a phone, pencil notes, undo, and a helper that lists the digit sets behind any sum.
Under the hood
How every puzzle is made
Puzzles are not pulled from a fixed list. Each one is built in your browser when you start it, then proven solvable by logic.
A layout, then a fill
A grid layout is built with every run between two and six cells long, no lone cells, and only a limited number of fully white 2×2 squares — the pattern most likely to create ambiguity. Digits 1–9 are then placed so no run repeats a digit, and the clues are the sums of what was placed.
A solver that counts
A backtracking solver then counts solutions for the resulting clues. If more than one exists, digits are adjusted and the grid is re-tested until exactly one remains. Only puzzles that pass are ever shown to a player.
Deterministic and resumable
Each puzzle comes from a numeric seed. Saving just the seed and your entries is enough to rebuild the exact same puzzle after a refresh, which is how an unfinished grid resumes without storing the board itself.
Design principles
What we hold to
- Instant to start
- Open the page and a puzzle is already on the board. No account wall, no download, no splash video — the grid is ready before you finish reading this sentence.
- Fair by construction
- Every grid is checked to have exactly one solution. You will never meet a puzzle that quietly needs a guess, and Check and Hint always agree with the answer.
- Yours to keep
- Wins, streaks and best hint-free times for each size live on your device. An unfinished puzzle resumes after a refresh. There is no login because there is nothing to log in to.
- Free, for real
- The whole game is free. No energy meters, no interstitial video between puzzles, no paywall on hints or notes.