Lesson 8 · Intermediate technique
Naked Pairs
Lock two matching candidates into two cells and remove them from the rest of the unit.
See the logic move
Use Next to reveal each reason. On the final step, tap the highlighted cell to complete the move yourself.
Live logical proof · Naked Pair
Step 1 of 3
Focus
row 1, column 1 and row 1, column 4 reserve candidates 5, 6 in row 1.
Ask about any cellTap a square on the board
Select an empty cell to see its legal candidates and why the other digits are blocked.
Why this works
- 1
row 1, column 1 and row 1, column 4 reserve candidates 5, 6 in row 1.
- 2
Inspect R1C1, R1C4 and then check its row, column, and 3x3 box.
What the board is showing
TargetThe cell currently being tested.R1C1, R1C4
Relevant unitThe row, column, or box controlling this move.Row 1
Explain it simply
Two cells share the same two numbers. Those numbers belong to the pair, even before we know their order.
Step by step
- Find two cells with the same two candidates.
- Confirm they share one unit.
- Reserve those candidates for the pair.
- Remove them from other cells in that unit.
Quick check: Can candidates 2 and 8 be removed from the two pair cells themselves?
No. Keep them in the pair and remove them only from other cells in the unit.
Turn logic into skill