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Kakuro
Small sums. Crossing possibilities.
Fill white squares with 1–9. Each across/down run has distinct digits adding to its clue; separate runs can repeat digits. Across clues sit above/right of the diagonal, down clues below/left. Sizes include the clue border. Type a digit, Shift+digit for notes, Backspace to erase. U/Y undo/redo, H hints, C checks, P pauses. Fresh puzzle · Puzzle .
Your achievements 0 / 8
How to play Kakuro
Fill every white square with a digit from 1 to 9. Each uninterrupted across or down run must add to its clue, and no digit may repeat within that run. Crossing runs share the number in their shared square.
Read the two clue triangles
An across sum appears above and to the right of the diagonal in a dark clue square; it applies to the white run immediately to its right. A down sum appears below and to the left and applies to the white run immediately below it. Dark squares and clues stay fixed.
There are no Sudoku boxes or whole-row uniqueness rules. The same digit may appear in separate runs of the same overall row or column. It is each individual run that needs distinct digits and the right sum.
The 7×7 and 9×9 size labels count the entire rendered grid, including its clue border. The number of white squares varies by puzzle. A white-square count in the header shows how much of the current puzzle is filled.
Follow the selected crossing runs
Select a white square to highlight its across and down runs. Their clue sums and the amount still needed remain in the header. A completed local run is labelled complete when its entries are distinct and meet its clue; that does not certify the other crossing entries or the whole puzzle.
Enter a digit with the number pad or keyboard. Conflicting repeats, incorrect completed sums and arithmetic that cannot finish a run are highlighted. You can correct an entry at any time. An unfinished or mistaken position does not cost a life or end the puzzle.
Pencil notes and useful history
Notes changes digit buttons to pencil marks in empty white squares. Choose the same mark again to remove it. A full digit replaces that square’s notes. Erase, Backspace, Delete or 0 clears your number or its notes. Notes are reminders, not filled answers or fixed restrictions on help.
Undo and Redo revisit entries and notes. A new edit clears the Redo branch. Restart clears the same clue grid as practice; New puzzle or a size change asks before replacing your work. Your first results, help and practice history stay recorded after Undo, Restart, reload or another variation of an original.
Run combinations
Across sets and Down sets show possible unordered sets of the remaining digits for the selected run. They use that run’s target, distinct-digit rule and entered values. They do not assign digits to positions or guarantee agreement with every crossing run or a full-puzzle finish.
Opening combinations counts as help immediately, including when no set can fit your entries. Simply selecting a square and reading its clue or remaining sum does not count as help. A completed run may show that no further digits are needed.
Hints that say what they know
Hint does not fill a number automatically. It can explain a forced value, diagnose a contradiction, explicitly check an entered value against the verified unique solution, or offer a clearly labelled verified value reveal. A reveal is not presented as a simple deduction. Use Fill suggested number if you want to enter an offered value.
Check describes current run constraints; it does not promise a future route from every partial grid. Asking for Hint or Check counts as help even when it only diagnoses a problem. Help, combinations, Undo and Restart remain recorded for that original puzzle.
Original cross-sum puzzles
This edition includes 48 original puzzle bases, 24 in each rendered size. Every base has one verified solution. Rotations, reflections and reversing the digit order with adjusted clues provide variations while keeping each base’s identity. Originals may recur; your collection counts each original once. Size labels are not standardized difficulty ratings, and not every position is promised a short or simple deduction.
Eight small milestones
Earn stars for a completed local run, your first original puzzle, completing each size, completing both sizes, a fresh first clear, and collections of three and ten originals. A run star recognises that run’s sum and distinct digits, rather than certifying the whole grid.
The fresh-clear star requires your first clear of an original before using Hint, Check, combinations, Undo or Restart on it. Assisted clears still join your collection. Replaying a completion does not add duplicate wins, and earned stars stay earned.
Comfortable controls
Tap a white square, then a number. Keyboard 1–9 enters a digit and Shift+digit toggles a note. Arrows skip dark squares in their direction; Home and End find the first or last white square of the row. N toggles Notes. U or Ctrl+Z undoes, Y or Ctrl+Shift+Z redoes, H asks for a hint, C checks, P pauses and R asks to restart. Escape closes help or returns from full screen.
Full screen gives the grid more room. On a small viewport, an accepted edit opens it automatically; a passive saved reload stays on the page. The grid remains in its own space while number tools, combinations and long explanations scroll separately. Pause hides the grid, notes and selected-run clue display and stops active time. Sound starts off, celebrations stay out of the play area, and motion follows your browser preference.
Keep your place
Your current clue grid, numbers, notes, selected white square, Notes mode, active time, sound preference and achievements save when browser storage is available. A returning active puzzle waits for Resume. A persistent warning explains when saving is unavailable; keep that page open because its in-memory progress may be lost after leaving. No account is needed.