These puzzles combine the logic of Sudoku with the arithmetic interplay of Kakuro and Fusion puzzles, for a fast, fresh and pleasurable solving experience.

The puzzles come in sizes of 4×4 through 9×9, but the most popular sizes are 5×5 and 6×6. A 5×5 is shown below. Cells are grouped into heavily-outlined areas, each of which has a result number and an arithmetic operator (+, – x or /).

Objective: Fill cells with digits 1 through 5 so that:

  • each digit occurs exactly once in each row, and in each column
  • the digits within each heavily outlined area, when combined using the given operator, equal the result number.
  • (If a single-cell area has no operator, assume “=” as the operator.)

For example, if a three-cell area has the clue “9+”, then the three cells must add up to 9. If a two cell area has a clue of “2-“, then one cell is two digits higher than the other.

Puzzle 58885938:

Tips: Sukendo puzzles are generally solved by alternating between Sudoku logic (eliminating digits as they occur elsewhere in the row or column) and applying the arithmetic you learned in grade school (factoring, subtraction.) Feel free to keep track of possible digits using “pencil marks” (small numbers drawn lightly in the corners of a cell) but if you need more than 3 pencil marks in a cell, it is generally not worth it. “Straight” areas (ones that are fully contained in a single row or column) will not contain repeated digits, but “bent” ones may, and often do, contain duplicates. Can’t think of a way to factor “4” into three digits? Don’t forget 2x2x1 or 4x1x1!

You can find a history of the puzzle at .

Generally, no trial and error is required. Experienced solvers learn to recognize certain result-and-operator combinations that are easy to resolve.

Sukendo are easily printed in black and white and played with a pen or pencil, and are popular with commuters.

Our puzzles are carefully graded by difficulty: Easy, Moderate, Hard and Challenging. All puzzles are rigorously tested to ensure that they have exactly one solution.

We provide puzzles and solutions in print-ready format (EPS, or Encapsulated Post-Script) as well as machine-readable format (XML), and can provide custom content and format as required.