Sudoku Candidate Strategy
Claiming Pairs Sudoku: How to Find and Use Claiming Pairs
Learn how a candidate restricted to one 3×3 box within a row or column can eliminate that candidate from other cells in the box. Claiming Pairs are one of the key forms of the Locked Candidates technique.
Line → Box
Claiming starts with a row or column. When all possible positions for one candidate fall inside the same box, that candidate is claimed by the line.
What Is a Claiming Pair in Sudoku?
A Claiming Pair is a candidate-elimination technique involving a row or column and a 3×3 box.
Suppose candidate 7 can appear in only two cells in a row. If both cells are inside the same box, one of those cells must contain 7.
The 7 for that box is therefore claimed by the row, so candidate 7 can be removed from the other cells in that box outside the row.
The same logic works vertically when all possible positions for a candidate in a column lie inside one box.
The Claiming Pair Rule
Candidate Restricted to One Box From a Line
Imagine candidate 4 appears only at R2C4 and R2C6 in row 2. Both cells are inside the top-middle box.
One of these cells must contain 4, so the 4 for the top-middle box must occur in row 2.
Remove candidate 4 from the other cells in the top-middle box that are outside row 2.
Why Claiming Pairs Work
Every row, column, and 3×3 box must contain each number exactly once.
If all possible positions for a number in a row are inside one box, the row guarantees that the number will be placed in that box.
The Key Logic
The line tells you which box must contain the candidate. That lets you remove the candidate from the rest of that box.
How to Find Claiming Pairs
Choose a Row or Column
Work with one line at a time.
Choose One Candidate
Look at the remaining positions for one missing number.
Find Two Possible Positions
Check whether the candidate appears only twice in the selected line.
Check the Box
Confirm that both positions are inside the same 3×3 box.
Inspect the Rest of the Box
Look at cells in the box outside the claiming line.
Remove the Candidate
Delete the claimed candidate from those other cells.
Rescan the Puzzle
The elimination may reveal a single, pair, triple, or another Locked Candidate.
Claiming Pair Example in a Row
Suppose candidate 6 appears in row 5 only at R5C1 and R5C3. Both cells are inside the middle-left box.
One of those two cells must contain 6, so the 6 for the middle-left box must be in row 5.
Remove candidate 6 from the other cells of the middle-left box outside row 5.
Claiming Pair Example in a Column
Suppose candidate 8 appears in column 5 only at R1C5 and R3C5. Both cells are inside the top-middle box.
The 8 for that box must therefore be in column 5.
Remove candidate 8 from other cells in the top-middle box outside column 5.
Claiming Pairs vs. Pointing Pairs
Learn the reverse direction in our Pointing Pairs Sudoku guide.
Claiming Pairs and Locked Candidates
Claiming Pairs are part of the broader Locked Candidates family.
Pointing is usually described as box → line. Claiming is line → box.
For the full concept, read our Locked Candidates Sudoku guide.
Claiming Pairs and Claiming Triples
The same logic can involve three candidate positions. If all possible positions for a candidate in one row or column are three cells inside the same box, that candidate is still claimed by the line.
You can remove that candidate from the other cells in the box outside the line. This is often called a Claiming Triple.
When Is It Not a Claiming Pair?
❌ Positions Span Two Boxes
If the candidate positions in the line are spread across different boxes, the line does not claim one box.
❌ Another Position Exists
If the candidate has another possible position in the line outside the box, the claiming restriction is not valid.
❌ You Remove From the Pair
Keep the candidate in the original claiming cells. Eliminations happen elsewhere in the box.
❌ You Confuse It With Pointing
Claiming starts with a line. Pointing starts with a box.
How to Practise Claiming Pairs
1. Use Candidate Notes
Candidate positions make box-line interactions easier to see.
2. Scan Row by Row
Look for numbers whose remaining positions fall inside one box.
3. Repeat With Columns
The same pattern can appear vertically.
4. Rescan After Eliminations
A claiming elimination can reveal singles, pairs, triples, or another Locked Candidate.
Related Sudoku Techniques
🔒 Locked Candidates Sudoku
Learn the parent technique covering both Pointing and Claiming.
👉 Pointing Pairs Sudoku
Learn the reverse box-to-line version of Locked Candidates.
👯 Naked Pair Sudoku
Learn how two cells reserve two candidates.
🧠 Advanced Sudoku Techniques
Explore SudokuLoop's broader solving-technique cluster.
Frequently Asked Questions
What is a Claiming Pair in Sudoku?
A Claiming Pair occurs when a candidate is restricted to two cells in a row or column and both cells lie inside the same 3×3 box.
How do you use a Claiming Pair?
Remove the claimed candidate from other cells in the same box outside the claiming row or column.
Are Claiming Pairs the same as Pointing Pairs?
No. Claiming works from line to box, while Pointing works from box to line.
Is Claiming part of Locked Candidates?
Yes. Claiming is one of the two main Locked Candidates patterns.
Can Claiming involve three cells?
Yes. Three positions in the same box can form a Claiming Triple using the same logic.
Practise Claiming Pairs
Open a Medium or Hard Sudoku puzzle, turn on Notes, and scan rows and columns for a candidate whose possible positions are all contained inside one 3×3 box.