Fill the grid with digits 1–9 that sum to each clue. No repeats allowed in any run.
Kakuro is a number crossword puzzle that combines the logic of Sudoku with the arithmetic of a crossword. Invented in Japan, the name is a portmanteau of "kasan kurosu" (addition cross). Each puzzle features a grid of black clue cells and white answer cells. The clue cells contain numbers indicating the required sum of adjacent answer cells in a horizontal or vertical run.
Each white cell must contain a digit from 1 to 9. The digits in each run (horizontal or vertical group of consecutive white cells) must add up to the clue number, and no digit can repeat within a single run. The challenge lies in finding the right combination of digits that satisfies all intersecting clues simultaneously. Use the sum helper to see all possible digit combinations for any clue.
Tap a white cell to select it, then enter a digit 1–9 using the number pad or keyboard. The digits in each run must add up to the clue shown in the adjacent black cell, and no digit can repeat in any run. Use the sum helper by tapping a clue cell to see all valid digit combinations. Enable error checking to spot mistakes as you go.
Many puzzle enthusiasts consider Kakuro more challenging than Sudoku because it requires both logical deduction and arithmetic. You need to identify which digit combinations sum to a target, then narrow them down by cross-referencing intersecting runs. However, smaller Kakuro puzzles (6×6) can be very approachable for beginners.
Key unique combinations to memorize: Sum 3 in 2 cells = {1,2}. Sum 4 in 2 = {1,3}. Sum 16 in 2 = {7,9}. Sum 17 in 2 = {8,9}. Sum 6 in 3 = {1,2,3}. Sum 7 in 3 = {1,2,4}. Sum 23 in 3 = {6,8,9}. Sum 24 in 3 = {7,8,9}. Sum 10 in 4 = {1,2,3,4}. Sum 30 in 4 = {6,7,8,9}. These "forced" combinations where only one set of digits works are the key to solving Kakuro efficiently.