Kakuro
Kakuro Sum 16 — All 2-Cell Combinations
Updated June 10, 2026 · 2 min read
A 2-cell Kakuro run with a clue of 16 has 1 valid combination. Each cell must contain a unique digit from 1 to 9, no repeats.
Forced combination. A 2-cell run summing to 16 can only use digits 7, 9. Both values are fixed — only their order within the run remains.
Valid combinations
| Digits (any order) | Sum |
|---|
| 7 + 9 | = 16 |
What you know immediately
The digits 7, 9 appear in every valid combination — certain in this run regardless of which combination applies.
Digits 1, 2, 3, 4, 5, 6, 8 never appear in any valid combination — eliminate them immediately from all intersecting clues.
Why this clue is special
Sixteen over two cells is the high-end magic clue mirroring 4: only 7 and 9 fit, because 8+8 would repeat. Together with 17-in-two it dominates the top of the digit range — any cell shared between a 16-in-two and a 17-in-two run must be the 9, since 9 is the only digit the sets {7,9} and {8,9} have in common. That single observation cracks a remarkable number of published puzzles.
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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