Sudoku Candidate Strategy
Pointing Pairs Sudoku: How to Find and Use Pointing Pairs
Pointing Pairs help you eliminate candidates by connecting a 3×3 box with a row or column. When a candidate can appear in only two cells inside a box and both cells share the same line, that candidate can be removed from the rest of the line outside the box.
Box → Line
A Pointing Pair starts inside a 3×3 box and points toward a row or column.
Choose a Box
Start by examining the candidates inside one 3×3 box.
Find the Alignment
Find a candidate restricted to two cells that share one row or column.
Eliminate Outside
Remove that candidate from the rest of the row or column outside the box.
What Is a Pointing Pair in Sudoku?
A Pointing Pair is a candidate-elimination technique that connects a 3×3 box with a row or column.
Suppose candidate 7 can appear in only two cells inside one 3×3 box. If both of those cells lie in the same row, then one of those two cells must eventually contain 7.
That means candidate 7 cannot appear anywhere else in that row outside the box.
The same logic works vertically. If the two possible locations for a candidate inside a box share one column, that candidate can be removed from other cells in the column outside the box.
The Pointing Pair Rule
Candidate Locked to One Line Inside a Box
Imagine candidate 4 appears only twice inside the top-left 3×3 box.
Both cells are in row 2. Therefore, the 4 for this box must be placed somewhere in row 2.
Remove candidate 4 from every other unsolved cell in row 2 outside the top-left box.
Why Pointing Pairs Work
Every 3×3 box must contain each number from 1 to 9 exactly once.
If candidate 4 has only two possible locations inside a box, then the final 4 for that box must occupy one of those two cells.
If both possible cells are on the same row, that guarantees that row will receive its 4 from inside that box.
The Key Idea
The box tells you where the candidate must occur.
The shared row or column tells you where that candidate cannot occur.
How to Find Pointing Pairs
Choose a 3×3 Box
Work with one box at a time instead of searching the whole grid randomly.
Choose One Candidate
Look at where one missing number can still appear inside that box.
Find Two Possible Cells
Check whether that candidate is restricted to exactly two cells inside the box.
Check Their Alignment
The two candidate cells must share the same row or the same column.
Follow the Line Outside the Box
Continue along the shared row or column beyond the 3×3 box.
Remove the Candidate
Remove the pointing candidate from other unsolved cells along that line outside the box.
Rescan After the Elimination
The removal may reveal a single, pair, triple, or another Locked Candidate.
Pointing Pair Example in a Row
Suppose candidate 6 appears in only two cells inside the middle-left 3×3 box:
Both possible locations are in row 5.
Therefore, one of R5C1 or R5C3 must contain 6.
Candidate 6 can be removed from other cells in row 5 outside that 3×3 box.
Pointing Pair Example in a Column
Now suppose candidate 8 appears only twice inside the top-middle box:
Both possible locations are in column 5.
Therefore, the 8 for this box must appear somewhere in column 5.
Remove candidate 8 from other unsolved cells in column 5 outside the top-middle box.
Pointing Pairs and Pointing Triples
The same logic is not limited to exactly two cells.
Sometimes a candidate can appear in three cells inside a 3×3 box, and all three cells are aligned on the same row or column.
Pointing Triple
If candidate 3 can appear only in three cells inside a box and all three are in row 7, then the 3 for that box must appear in row 7.
Candidate 3 can therefore be removed from the remaining cells of row 7 outside the box.
The underlying logic is identical: the candidate is locked to one line inside the box.
Pointing Pairs vs. Locked Candidates
Pointing Pairs belong to the broader family of techniques known as Locked Candidates.
Our Locked Candidates Sudoku guide explains the broader technique and both directions of the box-line interaction.
Pointing Pairs vs. Naked Pairs
The similar names can be confusing, but these are different techniques. Learn the other pattern in our Naked Pair Sudoku guide .
When Should You Look for Pointing Pairs?
A Box Has Few Candidate Locations
If a missing number has only two possible cells inside a box, immediately check whether those cells share a line.
Two Candidates Line Up
Two matching candidates aligned horizontally or vertically inside a box are worth checking.
Basic Singles Stop Working
Pointing Pairs are useful when direct placements are temporarily unavailable but candidate eliminations remain possible.
Medium and Hard Puzzles
This technique is especially useful as you move from beginner solving into candidate-based strategies.
When Is It Not a Pointing Pair?
❌ The Cells Do Not Share a Line
If the two candidate positions are in different rows and different columns, they do not form a Pointing Pair.
❌ Another Position Exists in the Box
If the candidate can also appear elsewhere in the same box outside the shared line, the candidate is not locked to that line.
❌ You Eliminate Inside the Pair
The two candidate positions inside the box remain possible. The eliminations happen elsewhere along the shared line.
❌ You Treat It Like a Naked Pair
A Pointing Pair tracks one candidate across two cells. It does not require those cells to contain exactly the same two candidates.
Common Pointing Pair Mistakes
❌ Looking at the Whole Grid
Pointing Pairs begin inside one 3×3 box. Start there and then follow the row or column outward.
❌ Forgetting the Alignment
The candidate locations must all share the same row or column for the elimination to be valid.
❌ Removing the Wrong Candidate
Only remove the candidate that is locked inside the box, not every candidate contained in the two cells.
❌ Eliminating From the Wrong Line
If the pair shares a row, eliminate along that row. If it shares a column, eliminate along that column.
How to Practise Pointing Pairs
1. Turn On Candidate Notes
Pointing Pairs become much easier to recognize when candidate positions are visible.
2. Scan Box by Box
Check each 3×3 box systematically instead of jumping randomly between cells.
3. Follow One Candidate
Pick one missing number and identify all of its possible locations inside the box.
4. Look for Alignment
Train yourself to notice when the candidate positions form a horizontal or vertical line.
5. Check Outside the Box
Once you see the pointing pattern, immediately follow the shared line outside the box for eliminations.
Pointing Pairs Practice Checklist
- 1. Did you start inside one 3×3 box?
- 2. Is one candidate restricted to only two cells?
- 3. Are both candidate cells in the same row or column?
- 4. Are there no other locations for that candidate inside the box?
- 5. Did you follow the shared line outside the box?
- 6. Did you remove only the pointing candidate?
- 7. Did you keep the candidate in the original pair cells?
- 8. Did you rescan after making the eliminations?
Related Sudoku Techniques
🔒 Locked Candidates Sudoku
Learn the broader family of box-line candidate restrictions that includes Pointing Pairs.
👯 Naked Pair Sudoku
Learn how two cells can reserve two candidates inside a single Sudoku unit.
🕵️ Hidden Pair Sudoku
Find two candidate numbers that are restricted to the same two cells.
3️⃣ Naked Triple Sudoku
Expand pair logic to three cells containing only three candidate numbers.
✖️ X-Wing Sudoku
Continue into a more advanced candidate-position pattern across rows and columns.
🧠 Advanced Sudoku Techniques
Explore the full collection of candidate, subset, fish, wing, rectangle, and coloring strategies.
Frequently Asked Questions
What is a Pointing Pair in Sudoku?
A Pointing Pair occurs when one candidate can appear in only two cells inside a 3×3 box and both cells are aligned in the same row or column.
How do you use a Pointing Pair?
Once the candidate is locked to one row or column inside the box, remove that candidate from other cells along the same line outside the box.
Are Pointing Pairs the same as Naked Pairs?
No. A Pointing Pair tracks one candidate restricted to two aligned cells inside a box. A Naked Pair involves two cells that contain only the same two candidate numbers between them.
Is a Pointing Pair a Locked Candidate?
Yes. Pointing is one form of the broader Locked Candidates technique.
Can Pointing Pairs work with three cells?
Yes. If three possible positions for the same candidate inside a box all share one row or column, the same elimination works. This is commonly called a Pointing Triple.
Where should I look for Pointing Pairs?
Start inside a 3×3 box. Look for a candidate with only two possible locations, then check whether those locations share a row or column.
Practise Pointing Pairs
Open a Medium or Hard Sudoku puzzle, use candidate notes, and scan each 3×3 box for a candidate restricted to one row or column.