About Kakuro
Kakuro — cross sums — played as a page of a merchant house's ledger. Every white cell takes a digit from 1 to 9; every run of white cells adds up to the figure written at its head, above the diagonal for the run going right and below it for the run going down; and no digit appears twice in one run. That last rule is the whole game: it turns a sum into a short list of possible digit sets, and the crossings decide between them.
Three hundred and twenty pages in five sizes, from a Tally you finish in three minutes to a Reckoning that takes half an hour, and the pages inside each size are ordered by measured difficulty rather than by a guess. Every one of them was kept only because the solver finished it without ever branching, so no page in this ledger needs a guess — that is the generator's accept test, not a promise in the small print.
The page does not know its own answer. The build ships the layout and the clues and nothing else, so there is no Check button and no hint that could leak one: a page is finished when the rules agree — every cell written, every run summing, nothing repeated. What you do get is what the inside cover of every kakuro book gives you, tapping a clue prints every combination it can be, and the keypad dims the digits that cannot stand in the cell you are on.
Each page keeps a public best time, and the Day's Page is one shared puzzle a day — drawn from a different ledger each weekday, and never the same page twice until that ledger has been through.
How to play
- Pick a ledger — Tally 6×6, Daybook 8×8, Ledger 9×11, Assay 9×14 or Reckoning 9×17 — and open a page. The clock starts as the page is dealt.
- Tap a white cell, then a digit. The same digit again rubs it out; Marks writes small, several to a cell, and nothing but you ever touches those.
- A run that is full and does not add up, or that repeats a digit, shows its own figure in red. Nothing else is ever told to you.
- Start where the arithmetic is forced: a 3-in-two can only be 1 and 2, a 16-in-two only 7 and 9, and a 45-in-nine is every digit there is. The crossings do the rest.
- The clock does not stop, and leaving a page keeps everything — the digits, the marks and the time. A page you come back to is yours to finish, but only a page done in one sitting takes the record.
Controls
| Click · Tap | Choose a cell, then a digit |
|---|---|
| 1 – 9 | Write the digit |
| 0 · Backspace | Rub it out |
| ↑ ↓ ← → | Move between cells |
| M | Pencil marks on and off |
| U · Ctrl+Z | Undo |
320 pages plus a daily, every one proven to have a single answer reachable without guessing. The best time on each page is public; your own times, and the page you are in the middle of, stay in this browser.
