GridWits
Easy tier Technique 3 of 11 Used by Smart Hint

Rejected Cell's Neighbors

Rejected cells can never touch, so every cell next to a rejected one is kept.

How it works

  1. 1The center cell is already known to be rejected.
  2. 2Rejected cells can never touch, so every cell next to it is kept — mark all four neighbors Keep.
1 2 3 4 5 6 7 8 9
  • Kept
  • Rejected
  • Cells that establish the pattern
  • Where the conclusion lands
Next in the ladder Duplicate of a Kept Cell →

Once a cell is kept, its number can't repeat among kept cells — every other copy in that row and column is rejected.