Sudoku and Kakuro are both grid-based logic puzzles you solve by pure deduction, so solvers naturally wonder how alike they really are. The short answer: Kakuro is very close to Sudoku. Below we lay out what the two share, where they part ways, and whether the skills you have built on Sudoku will carry over.
- Grid: Variable, black-and-white
- Closeness to Sudoku: Very Close
- Also called: Cross Sums, Kakro
What is Kakuro?
A crossword-shaped grid where you fill white cells with 1–9 so each across or down run adds up to its clue, with no digit repeated inside a run. Here are the rules in full:
- The grid mixes black and white cells like a crossword; you fill only the white ones.
- Each horizontal or vertical run of white cells has a clue giving the sum of its digits.
- Digits run 1–9 and never repeat within a single run — though the same digit can appear in different runs.
What a Kakuro looks like
A Kakuro looks like a crossword. Black cells carry the clues — a number with "▸" is the sum of the white run to its right, a number with "▾" the sum of the run below it. Here is a small solved Kakuro: the top row of clues drives the columns, the left column of clues drives the rows.
A solved 3×3 Kakuro: rows 3▸ (1+2) and 7▸ (3+4), columns 4▾ (1+3) and 6▾ (2+4).
Solving each run is the combination logic of a Killer cage. Two different digits that add to 6, for instance, are only {1, 5} or {2, 4} — the same short list you would write for a two-cell "6" cage in Killer Sudoku.
Before other clues, a "6" run is {1,5} or {2,4} — pure combination reasoning, just like Killer.
What Kakuro shares with Sudoku
- Both are pure-logic, single-solution puzzles solved by deduction, never guessing.
- The "no repeats in a unit" rule is shared — a Kakuro run is like a Sudoku row you must also make sum to a target.
- Both reward pencil-mark bookkeeping and sum-combination analysis.
How Kakuro differs from Sudoku
- Kakuro is built on arithmetic sums; Classic Sudoku has no maths at all.
- Runs vary in length and there is no 3×3 box or fixed grid size.
- A given Kakuro clue can repeat a digit across the whole grid — Sudoku forbids repeats in every row, column and box.
Do Sudoku skills transfer?
Kakuro is almost pure combination analysis, so the same skill you use for Killer cages — "which sets of distinct digits add to this sum in this many cells?" — is the core of every Kakuro. If you can solve Killer Sudoku, you already think in Kakuro.
Brush up on the technique that carries over: Killer Combinations.
The verdict
Kakuro is the closest arithmetic cousin to Killer Sudoku: same combination logic, wrapped in a crossword instead of a 9×9.
Prefer to stay with Sudoku?
If Kakuro appeals, these Sudoku variants scratch the same itch and you can read up on each here: