Kakuro
Kakuro Sum 7 — All 3-Cell Combinations
Updated June 10, 2026 · 2 min read
A 3-cell Kakuro run with a clue of 7 has 1 valid combination. Each cell must contain a unique digit from 1 to 9, no repeats.
Forced combination. A 3-cell run summing to 7 can only use digits 1, 2, 4. Both values are fixed — only their order within the run remains.
Valid combinations
| Digits (any order) | Sum |
|---|
| 1 + 2 + 4 | = 7 |
What you know immediately
The digits 1, 2, 4 appear in every valid combination — certain in this run regardless of which combination applies.
Digits 3, 5, 6, 7, 8, 9 never appear in any valid combination — eliminate them immediately from all intersecting clues.
Why this clue is special
Seven over three cells is forced to 1, 2 and 4 — the second-lowest 3-cell clue. The combination 1+2+4 skips the 3 (1+3+3 would repeat), a detail worth internalizing because beginners habitually pencil a 3 into these runs. If a crossing clue requires a 3 in a shared cell, that cell simply isn't part of a valid 7-in-three, and you've found an error somewhere.
Solving with this clue
- Cross out combinations made impossible by digits already placed in the run
- Find digits present in all remaining combinations — those are certain placements
- Find digits absent from all remaining combinations — remove from intersecting clues
- When one combination remains, all digits in the run are determined
Use intersections: A shared cell must satisfy both its row clue and column clue. Digits that don't appear in valid combinations for either clue are eliminated. This cross-elimination often reduces options to one quickly.
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