How to Play Kakuro

Overview

Kakuro (also known as Cross Sums) is a number puzzle that combines crossword structure with arithmetic. Fill white cells with digits 1-9 so each run adds up to its clue, without repeating any digit within a run.

Video Tutorial

Rules

  • 1Fill white cells with digits 1-9.
  • 2Clue cells show sums: top-left = sum below, bottom-right = sum to the right.
  • 3Each run must add up to its clue.
  • 4No digit can repeat within a single run.

Key Combinations

2 Cells
3 = 1+2
17 = 8+9
3 Cells
6 = 1+2+3
24 = 7+8+9
4 Cells
10 = 1+2+3+4
30 = 6+7+8+9
Remember
Sum of 1-9 = 45

Controls

ClickSelect a cell
1-9 KeysEnter a digit
P KeyToggle pencil mode
Ctrl+ZUndo last move

Solving Strategies

Unique Combinations

Start with clues that have only one possible combination (like 17 in 2 cells = 8+9).

Cross-Reference

Use intersecting runs to narrow down possibilities at shared cells.

Calculate Remainders

When a run has one empty cell, calculate: clue minus filled digits.