Hidden Pair Practice Puzzles

Every puzzle below is verified to feature the Hidden Pair as its hardest required technique — of the 65,284 puzzles in our library, 20,397 require it and 8,624 need nothing harder. New to the pattern? Learn the Hidden Pair or see a worked example first.

How to drill the Hidden Pair

A Hidden Pair is two digits that can only live in the same two cells of a unit. Those cells may be crowded with other candidates, and that clutter is exactly why the pattern is hard to see — the eye is drawn to sparse cells, and a Hidden Pair usually sits in busy ones.

The drill here is a counting habit rather than a looking habit. Take a unit and count, for each digit still missing, how many cells could hold it. Two digits that both come back with the same two cells are a Hidden Pair, and every other candidate in those two cells can be deleted. The elimination happens inside the pair's own cells, which is the opposite of a Naked Pair and the thing to keep straight.

These puzzles are the best argument on the site for full pencil marks. Hidden Pairs are close to invisible without them and fairly mechanical with them.

Curated Hidden Pair puzzles

  1. Practice puzzle #1 — 25 givens · needs Naked Single, Hidden Single, Hidden Pair
  2. Practice puzzle #2 — 24 givens · needs Naked Single, Hidden Single, Hidden Pair
  3. Practice puzzle #3 — 23 givens · needs Naked Single, Hidden Single, Hidden Pair
  4. Practice puzzle #4 — 24 givens · needs Naked Single, Hidden Single, Hidden Pair
  5. Practice puzzle #5 — 24 givens · needs Naked Single, Hidden Single, Hidden Pair
  6. Practice puzzle #6 — 25 givens · needs Naked Single, Hidden Single, Hidden Pair
  7. Practice puzzle #7 — 24 givens · needs Naked Single, Hidden Single, Hidden Pair
  8. Practice puzzle #8 — 26 givens · needs Naked Single, Hidden Single, Hidden Pair
  9. Practice puzzle #9 — 26 givens · needs Naked Single, Hidden Single, Hidden Pair
  10. Practice puzzle #10 — 24 givens · needs Naked Single, Hidden Single, Hidden Pair
  11. Practice puzzle #11 — 26 givens · needs Naked Single, Hidden Single, Hidden Pair
  12. Practice puzzle #12 — 24 givens · needs Naked Single, Hidden Single, Hidden Pair
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Hidden Pair practice FAQ

How many Sudoku puzzles require the Hidden Pair technique?
Of the 65,284 puzzles in the Precision Sudoku library, 20,397 require the Hidden Pair to solve, and 8,624 can be completed with nothing harder than the Hidden Pair. Every puzzle is verified by a solver that records the exact techniques needed.
What is the difference between a Hidden Pair and a Naked Pair?
A Naked Pair is two cells containing only two candidates, and it eliminates those digits from the rest of the unit. A Hidden Pair is two digits that can only go in two cells, and it eliminates every other candidate from inside those two cells. One prunes outward, the other prunes inward.
Why are Hidden Pairs so much harder to see than Naked Pairs?
Because the cells look unremarkable. A Naked Pair announces itself as two sparse matching cells, while a Hidden Pair sits inside cells carrying several other candidates. Finding it means counting where each digit can go rather than reading what each cell contains.