How to Play Kakuro

Kakuro mixes a crossword-style layout with pure arithmetic. Each white square belongs to an across and/or down run, and the shaded clue cells tell you the exact sum you must hit without repeating digits.

Reading the grid

  • The triangle in the bottom-left of a clue cell labels the sum for the across run to its right.
  • The triangle in the top-right labels the sum for the down run below it.
  • Runs vary in length—long stretches tend to carry larger totals and invite combination analysis.

Quick start checklist

  1. Begin with short runs such as 3-in-2 (must be 1+2) or 4-in-2 (must be 1+3) to claim guaranteed digits.
  2. Mark pencil candidates by holding Shift and tapping numbers whenever a placement is uncertain.
  3. Compare crossing runs—when one narrows to {2,5}, the other cannot use 2 or 5 elsewhere in that run.

Work an example

Suppose a horizontal clue of 16 spans three cells. The only non-repeating triples that sum to 16 are {1,6,9}, {2,5,9}, {3,4,9}, {3,6,7}, and {4,5,7}. If the overlapping vertical runs already use 1 and 6, you can strike every combination containing those digits and zero in on the remaining options.

Avoid these early mistakes

  • Do not repeat digits within a run—even if the totals work out, duplicated numbers break the Kakuro rules.
  • Recalculate after every placement; a new digit often tightens another run to a single option.
  • Write down eliminations. The app’s candidate marks mirror the notes veteran solvers keep on paper.

Level up your solving

Once the basics feel natural, dive into our technique library. Start with sum singles and cross sums, then progress to combination pruning and advanced locked-set strategies to master tougher grids.