Kakuro Revisited

Last Cell in a Run

When a run has only one empty cell left, the clue sum minus the digits already in the run gives that cell.

Level 1 Basics Technique 01

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Across 10 (r2c2–r2c3) holds a 9 and one empty cell. 10 − 9 = 1, so r2c3 must be 1.

placed key digits

Why it works

Every run must add up to its clue sum and may not repeat a digit. Once all but one of its cells are filled, the last digit is not a guess: it is exactly what is missing.

This is the most common step in an easy Kakuro. It is also the step that starts almost every puzzle, because a run of two cells with one digit given hands you the other one for free.

How to spot it

  1. Find a run with exactly one empty cell.
  2. Add the digits already placed in that run.
  3. Subtract the total from the clue sum. The result is the digit of the empty cell.
  4. Check that the digit does not already appear in the run, or in the other run through the cell.

Practice it

Open the app, choose a level that uses this technique, and ask the coach for the next step. Every hint links back to this guide.