GridWits
Hard tier Technique 9 of 21 Smart Hint: Skyscrapers

Hidden Pair

Two heights only fit in the same two cells of a row or column — strip those cells down to just those two.

How it works

  1. 1Heights 4 and 5 have to appear somewhere in this row — every height does.
  2. 2The first three cells have already lost both, so the 4 and the 5 are squeezed into the last two cells.
  3. 3Two heights with only two cells to live in: those cells hold the 4 and the 5 between them, in some order.
  4. 4Strike everything else from both — even though neither is pinned to a single height yet. That's what makes it HIDDEN: the pair was buried under other candidates rather than sitting there in plain sight.
1 2 3 1 2 3 1 2 3 1 2 4 5 3 4 5
  • Height ruled out
  • Relationship — The arrow shows which cells support the deduction.
  • Conclusion — The final arrow lands beside the proved or ruled-out height.
Next in the ladder Naked Triple →

Three cells in a row or column whose candidates combine to exactly three heights — eliminate those heights elsewhere in the line.