What is candidate elimination in Sudoku?
It is the logical removal of a digit from a cell’s possible values after a rule or pattern proves that digit cannot go there.
Pure Sudoku
Beginner to advanced technique
Candidate elimination turns restrictions into progress.
Every logical Sudoku technique either places a forced digit or proves that a candidate cannot occupy a cell. Clean eliminations make the next placement visible.
- Level
- Beginner to advanced
- Pattern
- Remove only candidates disproved by a shared unit or pattern
- Outcome
- Logical progress
Focused example
A placed 6 removes candidate 6 from every peer in the unit.
The highlighted cells show the exact scope of the pattern. Read the candidates before making an elimination.
How it works
Apply the pattern in four checks.
- Start with direct peer elimination from placed digits.
- Check box-line interactions, pairs, and triples for additional restrictions.
- Remove only candidates covered by the exact pattern.
- Re-scan for naked and hidden singles after every elimination.
Know the difference
Use the pattern only when every condition is true.
An elimination is not a guess and may not place a digit immediately. It records a proven impossibility so later candidate sets become smaller and clearer.
After the move, re-scan the affected unit for singles before searching for another advanced pattern.
Common mistake
Protect the logic before erasing a candidate.
Apply the elimination only inside the exact shared unit covered by the pattern. Similar-looking candidates elsewhere are not part of the deduction.
If any required condition is missing, leave the candidates in place and continue scanning.
Continue playing
Choose your next Sudoku route.
FAQ
Quick answers before you play.
Should I erase a candidate if it merely looks unlikely?
No. Remove a candidate only when a row, column, box, or valid solving pattern proves it impossible.
What should I do after an elimination?
Scan the affected units for newly created naked singles, hidden singles, pairs, or triples.
Practice loop
Find it on a live board.
Pause when the board slows down, check the candidate conditions, make one justified move, and scan again.