A quiet place for numbers.

A FIELD GUIDE TO KAKURO

Crosswords, with sums.

Fill every white square with a digit from 1 to 9. A clue marked → is the sum of the uninterrupted white squares to its right. A clue marked ↓ is the sum of the uninterrupted white squares below it.

Within each run, every digit must be different. There is no rule about a whole row or column beyond its separate runs.

Click a square and use the keypad or number keys. Toggle Pencil marks (N) to record candidates. The crossing panel lists all possible digit sets for both clues, filtered by digits already written. Notes are yours to edit; they do not restrict the solution.

Green clues are complete. Red digits flag a duplicate, overfull, or impossible sum in that run. Reveal a digit finds the next empty square from the puzzle's verified solution; reveals count as assistance. If your entries cause a contradiction, erase or undo first.

All 25 pages are available from the menu. Progress and pencil marks save on this device when storage is available.

SOURCE & CRAFT

Sum & Cedar

Uses the original Kakuro engine, combination enumerator and 25 baked puzzles from z-biz-game/z-biz-game-kakuro-cos, commit 55d9a8e, under the MIT license. New English interface, accessible DOM board, note controls and local saves. Not affiliated with the original author.

The cedar writing desk was generated with a GPT image model, optimized locally, and placed beneath the playable board. No remote assets, account, model calls or backend.

Complete readable code: app.js, engine.js, combos.js, levels.js, style.css. Modification notes.