Hidden Quad Practice Puzzles

A Hidden Quad is four digits that can only be placed within the same four cells of a unit. All other candidates are then removed from those four cells, leaving just the quad.

Every puzzle below is verified to feature the Hidden Quad as its hardest required technique — of the 65,284 puzzles in our library, 405 require it and 379 need nothing harder. New to the pattern? Learn the Hidden Quad or see a worked example first.

Curated Hidden Quad puzzles

  1. Practice puzzle #1 — 26 givens · needs Naked Single, Hidden Single, Hidden Quad
  2. Practice puzzle #2 — 23 givens · needs Naked Single, Hidden Single, Hidden Quad
  3. Practice puzzle #3 — 26 givens · needs Naked Single, Hidden Single, Hidden Quad
  4. Practice puzzle #4 — 24 givens · needs Naked Single, Hidden Single, Omission, Hidden Quad
  5. Practice puzzle #5 — 23 givens · needs Naked Single, Hidden Single, Omission, Hidden Quad
  6. Practice puzzle #6 — 23 givens · needs Naked Single, Hidden Single, Omission, Hidden Quad
  7. Practice puzzle #7 — 23 givens · needs Naked Single, Hidden Single, Omission, Hidden Quad
  8. Practice puzzle #8 — 24 givens · needs Naked Single, Hidden Single, Omission, Hidden Quad
  9. Practice puzzle #9 — 27 givens · needs Naked Single, Hidden Single, Naked Pair, Hidden Quad
  10. Practice puzzle #10 — 27 givens · needs Naked Single, Hidden Single, Omission, Hidden Quad
  11. Practice puzzle #11 — 23 givens · needs Naked Single, Hidden Single, Omission, Hidden Quad
  12. Practice puzzle #12 — 24 givens · needs Naked Single, Hidden Single, Naked Pair, Hidden Quad
Get a fresh Hidden Quad puzzle →

Hidden Quad practice FAQ

How many Sudoku puzzles require the Hidden Quad technique?
Of the 65,284 puzzles in the Precision Sudoku library, 405 require the Hidden Quad to solve, and 379 can be completed with nothing harder than the Hidden Quad. Every puzzle is verified by a solver that records the exact techniques needed.
What is the best way to practice the Hidden Quad?
Play puzzles where the Hidden Quad is the hardest move required, so every sticking point is an opportunity to apply it. It is the rarest of the hidden subsets; look for it in dense units where four digits cluster into four cells.
Can I play a Sudoku puzzle that needs exactly the Hidden Quad?
Yes. The curated puzzles on this page all feature the Hidden Quad as their most advanced required technique, and the practice button serves a fresh puzzle from the same verified pool whenever you want another.