Sudoku-YNext steps
Naked Pairs: two cells reserve two digits
A pair can eliminate candidates before you know which of its cells takes which digit. The two cells must share a unit and have exactly the same two candidates.
Practise on a board ↓Interactive practice · Your saved game is unchanged
Eliminate with a Naked Pair
D1 and D4 contain only {2,8}. Select every candidate you can remove from D7.
An original row D scenario. Small notes are complete under the stated conditions; large digits are placed values. Only the teaching row is shown.
Progress: 0 / 2
Show reasoning and answer
2 and 8 must occupy D1 and D4 in some order. Neither can go in D7, so D7 is left with 5.
LOOK · TRY · UNDERSTAND
Try it and see why
Is that really a pair?
The shown cells have complete notes. Check D1 and D4.
Our own partial teaching board, not a full puzzle. Large digits are placed values; small digits are candidates. Dots mean the cell is not described here. Complete candidate lists are part of the stated scenario, not calculated from the dots.
Green outline = evidence · Purple “try” = an assumption · Crossed out = removed candidate
Can this Naked Pair remove 8 from D7?
See the reasoning
D1 and D4 use 2, 8 in some order in row D. Other cells in the row cannot use either digit.
Digit set 1/9 · A different digit set in the same pattern, not a new full puzzle.
Read the source principles: HoDoKu — Naked Subsets
Check the condition, not just the shape
Change to a different row D, missing 2, 5 and 8, with the three empty cells shown. Can D1/D4 still eliminate 2 and 8 from D7 as a Naked Pair?
Check the reasoning
No. D4 can still be 5. For example, D1 = 2, D4 = 5 and D7 = 8 fill the missing row digits without repetition. The stated information therefore does not justify removing 8 from D7. This is not a claim about the solution of a complete puzzle.
On your game: check that exactly the same two candidates remain in each of two cells sharing a row, column or box. Eliminate only from other cells in that shared unit, then look for a new Single.
Check the condition
If two cells in one row, column or box both have only {2,8}, those cells must use 2 and 8 between them. Other cells in that shared unit cannot use either digit.
HoDoKu — Naked Subsets · SudokuWiki — Naked Candidates
D1 and D4 reserve 2 and 8 in row D. D7 keeps 5.
Example in row D
Suppose D1={2,8}, D4={2,8} and D7={2,5,8}. The pair reserves 2 and 8 for D1 and D4, leaving D7=5. You do not yet need to decide the order of the pair.
Try before revealing
If D4 instead has {2,6,8}, does the same deduction still work?
Show explanation
No. D4 could be 6, so those two cells no longer reserve just 2 and 8. The Naked Pair condition is missing.
Respect the shared unit
A pair in a row eliminates within that row, not everywhere the digits appear. If both cells also share a box, eliminations can apply in that box too. A single cell with two candidates is not a pair.
In Sudoku-Y
The Techniques scanner already recognizes naked pairs. It highlights the source cells and elimination targets while leaving you in control of your notes and answers.
References and further reading
Read the source explanations and compare them with our examples. Links are references, not endorsements or claims of affiliation.