Kakuro Game — Free Online Cross-Sum Puzzle, Easy to Devilish

How to play Kakuro

A crossword with digits: each run of white cells adds up to its clue, using 1–9 without repeats.

The grid has black clue cells and white cells. A clue cell shows the total for the run of white cells to its right (across) and/or below it (down).
Fill every white cell with a digit from 1 to 9.
The digits in a run must add up to its clue.
No digit may repeat within a run.

Choose a grid size and a difficulty, then press Generate Puzzle.
Click a cell and type a digit, or use the on-screen keypad. Notes switches to pencil marks.
Undo steps back; Force places one digit that has only one possible value; Check marks mistakes in red without giving away the answer.
Stuck? Send to Solver opens the same puzzle in the step-by-step solver. Send to Slate opens it as a board on the Slate whiteboard, to solve in front of a class.

Start with unique sums. Some totals have only one combination: 3 in 2 cells (1+2), 4 in 2 (1+3), 16 in 2 (7+9), 17 in 2 (8+9), 6 in 3 (1+2+3), 24 in 3 (7+8+9).
Cross the runs. A cell belongs to an across run and a down run. Only digits allowed by both can go there — the intersection often leaves one choice.
Must-have digits. A 4-cell run totalling 11 is always 1+2+3+5, so it must contain a 5 even before you know where.
Small and large ends. Low totals force small digits and high totals force large ones. A 2-cell 15 can only use 6, 7, 8 and 9.

The full guide, with a worked example and common mistakes: How to play Kakuro.

What does a clue cell with two numbers mean?

The number in the upper-right is the total for the run going across; the one in the lower-left is the total for the run going down.

Are there combination charts for Kakuro?

Yes — see the Kakuro combinations chart, which lists every total for runs of 2 to 9 cells and marks the ones with a single combination.

Can I solve a Kakuro from a book?

Build it in the Kakuro Solver: click cells to make them black, enter the clues, then solve step by step.

Is Kakuro harder than Sudoku?

It needs some arithmetic and combination knowledge, but the logic is similar. Easy Kakuro is a good next step after Sudoku.

What is the largest run?

Nine cells, which must contain every digit 1–9 and so always totals 45.