About Kakuro Revisited

A Kakuro (Cross Sums) puzzle generator, human-style solver, difficulty rater, trainer and coach, modelled on its sister project Hodoku Revisited.

What it is

Kakuro Revisited is a free, open-source progressive web app. It runs entirely in your browser: the generator, the solver, the difficulty rater and the coach all live in the page. No account, no server, and after the first visit it works offline.

How the engine works

• Sum partitions. Every sum and run length has a fixed table of digit sets. The solver works with those tables, not with brute force.
• A human solver. Twelve techniques, from the last cell in a run to contradiction forcing. Every step is sound: the solver never places or removes a digit without a proof.
• A deterministic generator. A puzzle is kept only when it has exactly one solution and the human solver finishes it. Otherwise it is discarded. Ambiguous fills are repaired, not shipped.
• A difficulty rater. The level comes from the hardest technique the puzzle needs and the length of the solve path.
• Exact tools where they matter. Assigning a known set of digits to the cells of a run is a bipartite matching problem, solved exactly in polynomial time.

Inspired by

The design owes a debt to the classic open-source Java Kakuro tools crozzsum, kakurohelper and jkakuro, and to the human-technique approach of Hodoku for Sudoku. The goal is the same: show the reasoning, not just the answer.

Open source

The source code is on GitHub under GPL-3.0-or-later. Bug reports and pull requests are welcome.

Contact

Email [email protected] or open an issue on GitHub. There is no mailing list and no account system.