Play Kakuro free in your browser — no download, no sign-up. Five grid sizes, seven difficulty tiers, a seeded daily challenge that's the same for every player worldwide, and shareable challenge links so you can send your best time to friends and see if they can beat you.
Kakuro was invented in 1966 by Canadian Jacob Funk for Dell Magazines as "Cross Sums." Japanese publisher Nikoli rebranded it as "Kakuro" (a contraction of kasan kurosu, "addition cross") in the 1980s and it became a phenomenon — second only to Sudoku in Japan's puzzle pantheon. This version preserves the original mechanics with combo-biased puzzle generation that guarantees every layout is logically solvable, plus the modern conveniences: notes, hints, undo, check, daily streak.
From the builder's desk
Kakuro taught me a lesson about engineering honesty that I now apply to every generator on this site. Early builds could hang the main thread while hunting for a guaranteed-unique large board — and a freeze of around 1.2 seconds, in a browser game, reads as a crash. Players don't see mathematical rigor; they see a page that stopped responding. So I made a deliberate trade: generation runs on a wall-clock budget, and if the budget expires, the generator accepts a rare non-unique board at the same size rather than ever freezing. Nobody notices a second valid solution. Everyone notices a hang. I stand by that call completely, and I'd rather say it here in plain words than pretend the trade-off doesn't exist.
The harder design problem, honestly, wasn't generating valid puzzles at all. It was making sure every board gives you real entry points — cells you can start solving from without guessing. A technically-correct Kakuro with no foothold is just a wall of white cells daring you to gamble. Getting the clue structure to offer a few forced openings, on every board, at every size, took longer than the solving engine itself did.
Those entry points come from the game's most beautiful property, and it's exactly the one newcomers ignore. Every run must hit its sum with unique digits, and that combination forces cells far harder than people expect. A three-cell run summing to 6 has exactly one digit set: 1, 2, and 3. A two-cell run summing to 3 must be 1 and 2. A two-cell run to 17 must be 8 and 9. These aren't clever deductions — they're the only possibilities that exist. And yet I watch players brute-force their way through cells the sum-combination already determined, testing digits one by one in a run that mathematics settled before they ever touched the board.
So here's how to actually start. Scan for the extreme runs first — the lowest sums in two cells, then the highest, then the forced three-cell sets like 6 and 24. Pencil those candidate sets in. Where two forced runs cross, the shared cell often collapses to a single digit immediately, and that one digit ripples outward through both runs, resolving neighbours you haven't even looked at yet. That cascade is the game. The feeling of one placement unlocking six others is why this puzzle has survived since the pencil-and-paper era, and it's what I wanted the browser version to preserve above everything else.
Play the small boards until the standard sum-sets live in your memory the way multiplication tables do. After that, the big grids stop being intimidating and start being long, pleasant walks. The daily resets at midnight — every player worldwide gets the same board, entry points and all.