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 Sudoku 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:
Where to play it
If it was Sudoku you came for, the level is the choice that matters more than the variant - Kakuro and Sudoku part ways on the rules, but a Sudoku grid can be a two-minute warm-up or an hour of work depending on nothing but how much of it you are given.
Difficulty and type are two separate dials here: the type sets the extra rule, the level sets how much of the grid you start with. Easy Sudoku leaves 36 of the 81 cells filled, so there is always an obvious next move somewhere; Evil Sudoku leaves 23, with no easy moves at all. Take it at the gentler end while the pattern is still new, and move up once it stops being a fight.