Play Now

Hidden Pairs / Triples / Quads

Visual diagram for hidden pairs triples quads Sudoku technique
See the pattern before reading the steps.

What It Is

Hidden subsets are numbers confined to the same limited cells in a unit—two numbers in two cells (pair), three in three cells (triple), four in four cells. Remove other candidates from those cells to expose the locked set.

When to Use

Mid-game with many pencil marks; when naked subsets are exhausted and you need to simplify dense candidate lists.

How to Apply (Step-by-Step)

  1. Survey a unit’s candidates: list where each missing number could go in a row/column/box.
  2. Find confined candidates: look for numbers limited to the same cells (two numbers to two cells, etc.).
  3. Confirm exclusivity: ensure no other cells hold those candidates.
  4. Eliminate other candidates from those cells: leave only the hidden set.
  5. Repeat for triples/quads.

If digits 2 and 4 only appear in two cells of a column, erase all other notes from those cells—revealing a hidden pair that simplifies the unit.

See also

Scanning / Cross-Hatching Single Candidate (Naked Single) Single Position (Hidden Single) Naked Pairs / Triples / Quads Hidden Pairs / Triples / Quads Pointing Pairs / Triples (Locked Candidates Type 1) Box–Line Reduction (Locked Candidates Type 2) X-Wing Swordfish Jellyfish XY-Wing XYZ-Wing W-Wing Alternating Inference Chains (AICs) Forcing Chains / Forcing Nets Nishio Coloring Multi-Coloring Uniqueness Techniques (Unique Rectangle etc.) Fish Variants (Finned X-Wing, Sashimi etc.) ALS Techniques (ALS-XZ, ALS Chains) Sue de Coq Pattern Overlay / Template Method
Ready to practise?
Try a fresh Sudoku puzzle now → /play