Sudoku Candidate Strategy
Naked Triple Sudoku: How to Find and Use Naked Triples
Learn how three cells containing only three candidate numbers can lock those numbers into the cells. Once you find a Naked Triple, remove the same candidates from every other cell in the row, column, or box.
3 Cells, 3 Candidates
If three cells in one unit contain only three candidate numbers between them, those candidates belong to those three cells.
Find Three Cells
Look for three unsolved cells in the same row, column, or box.
Check the Candidates
The combined candidates across those cells must contain exactly three numbers.
Remove Them Elsewhere
Remove those three candidates from every other unsolved cell in the same unit.
What Is a Naked Triple in Sudoku?
A Naked Triple is a Sudoku candidate technique involving three unsolved cells in the same row, column, or 3×3 box.
Between those three cells, there are only three possible candidate numbers.
Because three cells must eventually contain three numbers, those candidates are reserved for those three cells.
Therefore, the same three candidates can be removed from every other unsolved cell in that unit.
The cells do not need to contain identical candidate lists. They only need to use the same group of three candidate numbers between them.
The Naked Triple Rule
Three Cells Using Only Three Candidates
Suppose three cells in one row contain candidate combinations made only from 2, 5, and 8.
Those three cells must eventually contain 2, 5, and 8 in some order.
Remove candidates 2, 5, and 8 from every other unsolved cell in the same unit.
Why Is It Called a Naked Triple?
The triple is called naked because the important candidates are visible directly inside the three cells.
You do not need to search where three specific numbers can appear across the whole unit. Instead, you focus on what candidates are already contained in the three cells.
Think About the Cells First
With a Naked Triple, the cells tell you which three numbers are locked together.
This is the opposite perspective from a Hidden Triple, where you begin by tracking the candidates and discover the three cells that contain them.
How to Find a Naked Triple
Choose One Sudoku Unit
Examine one row, column, or 3×3 box at a time.
Look for Cells With Few Candidates
Start with unsolved cells containing only two or three candidates.
Group Three Cells
Check groups of three cells and combine all of their candidate numbers.
Count the Combined Candidates
If the three cells contain exactly three different candidates between them, you may have a Naked Triple.
Confirm the Triple
Make sure all three selected cells use only candidates from that same set of three numbers.
Remove the Triple Candidates Elsewhere
Delete those three candidates from every other unsolved cell in the same row, column, or box.
Rescan the Puzzle
The eliminations may reveal a single, pair, Locked Candidate, Hidden Triple, or another useful pattern.
Naked Triple Example
Suppose you are examining row 6 and find these three cells:
Across these three cells, the only candidates are 2, 5, and 8.
Therefore, R6C2, R6C5, and R6C8 must contain 2, 5, and 8 in some order.
If any other cell in row 6 contains candidate 2, 5, or 8, those candidates can be removed from that cell.
Why the Naked Triple Elimination Works
Every unsolved Sudoku cell must eventually contain exactly one number.
If three cells can contain only three numbers between them, then those three numbers must fill those three cells.
The Key Logic
Three cells require three values.
If only 2, 5, and 8 are possible across those cells, all three numbers are reserved for the triple.
There is therefore no possibility for 2, 5, or 8 to appear in another cell of that same unit.
Do All Three Cells Need Three Candidates?
No. This is one of the most important things to remember about Naked Triples.
Each cell may contain two or three candidates, as long as the combined candidate set across all three cells contains exactly three numbers.
Valid Naked Triple
All three cells together still use only 2, 5, and 8, so the Naked Triple is valid.
Naked Triples Can Appear in Rows, Columns, and Boxes
Row
Three cells in a row contain only three candidates between them.
Column
The same Naked Triple logic works vertically inside a column.
3×3 Box
Three cells within one box may also reserve three candidate numbers.
Naked Triple vs. Naked Pair
If Naked Triples feel difficult, first review our Naked Pair Sudoku guide . A Naked Triple uses exactly the same basic idea but expands it from two cells and two candidates to three.
Naked Triple vs. Hidden Triple
Easy Way to Remember
Naked Triple: start with the three cells.
Hidden Triple: start with the three candidate numbers.
For the opposite version of this technique, read our Hidden Triple Sudoku guide .
Naked Triple vs. Locked Candidates
For another useful candidate-elimination technique, continue with our Locked Candidates Sudoku guide .
When Should You Look for a Naked Triple?
Several Bivalue Cells Appear
Cells with only two candidates are excellent places to begin searching for a Naked Triple.
A Naked Pair Almost Works
If two related cells contain candidates from a small group but a third candidate and third cell are involved, check for a Naked Triple.
The Puzzle Has Many Notes
Naked Triples can reduce crowded candidate lists and make later solving patterns much easier to see.
Medium or Hard Sudoku
Naked Triples commonly become useful after singles, Naked Pairs, and simpler candidate eliminations no longer make progress.
When Is It Not a Naked Triple?
❌ The Three Cells Contain Four Candidates
If the combined candidate set contains four different numbers, the three cells are not a Naked Triple.
❌ The Cells Are in Different Units
All three cells must share one row, column, or 3×3 box.
❌ Only Two Cells Are Involved
If only two cells reserve two candidates, you have a Naked Pair rather than a Naked Triple.
❌ You Remove Candidates From the Triple Cells
With a Naked Triple, keep the three candidates inside the triple cells. Remove them only from the other cells in the unit.
Common Naked Triple Mistakes
❌ Expecting Identical Candidate Lists
The three cells do not need to show the same candidates. Their combined candidate set only needs to contain exactly three numbers.
❌ Confusing Naked Triple With Hidden Triple
Naked Triple removes its three candidates from other cells. Hidden Triple removes unrelated candidates from the three triple cells.
❌ Forgetting to Check the Whole Unit
After finding the triple, inspect every other unsolved cell in that row, column, or box for possible eliminations.
❌ Searching Randomly
Start with cells containing two or three candidates. This dramatically reduces the number of combinations you need to inspect.
How to Practise Naked Triples
1. Master Naked Pairs First
Naked Triple extends the same logic from two cells and two candidates to three cells and three candidates.
2. Scan One Unit at a Time
Work through one row, column, or box instead of looking across the entire grid.
3. Start With Small Candidate Lists
Focus first on cells containing only two candidates, then test nearby cells containing two or three candidates.
4. Combine Candidate Sets
Mentally combine the candidates from three cells and check whether only three unique numbers remain.
5. Check Every Other Cell
Once the triple is confirmed, look throughout the same unit for candidates that can be removed.
6. Rescan After Eliminations
A Naked Triple can reveal singles, Naked Pairs, Hidden Pairs, Locked Candidates, or other useful patterns.
Naked Triple Practice Checklist
- 1. Are the three cells in the same row, column, or box?
- 2. Have you selected exactly three cells?
- 3. Does their combined candidate set contain exactly three numbers?
- 4. Does every selected cell contain only candidates from that three-number set?
- 5. Did you remember that each cell does not need all three candidates?
- 6. Did you check the other cells in the same unit?
- 7. Are you removing only the Naked Triple candidates from those other cells?
- 8. Did you keep the candidates inside the triple cells?
- 9. Did you rescan the puzzle afterward?
Related Sudoku Learning Pages
👯 Naked Pair Sudoku
Start with the simpler two-cell version of the Naked Triple concept.
3️⃣ Hidden Triple Sudoku
Learn the opposite triple technique by tracking three candidate numbers restricted to three cells.
🕵️ Hidden Pair Sudoku
Find two candidate numbers restricted to the same two cells in one unit.
🔒 Locked Candidates Sudoku
Learn how box-line restrictions create candidate eliminations.
🧠 Advanced Sudoku Techniques
Explore pairs, triples, fish patterns, wings, rectangles, coloring, and other advanced solving strategies.
✖️ X-Wing Sudoku
Continue from candidate sets into a powerful single-candidate pattern.
Frequently Asked Questions
What is a Naked Triple in Sudoku?
A Naked Triple occurs when three cells in one row, column, or box contain only three candidate numbers between them. Those candidates can then be removed from all other cells in that unit.
How do you find a Naked Triple?
Look for three cells in one unit whose combined candidate set contains exactly three different numbers.
Do Naked Triple cells need identical candidates?
No. Candidate combinations such as 2/5, 2/8, and 5/8 can form a valid Naked Triple because only 2, 5, and 8 appear across the three cells.
What is the difference between Naked Triple and Hidden Triple?
Naked Triple starts with three cells containing only three candidates and removes those candidates from other cells. Hidden Triple starts with three candidates restricted to three cells and removes unrelated candidates from the triple cells.
Where can Naked Triples appear?
They can occur in a row, column, or 3×3 box.
Is Naked Triple harder than Naked Pair?
Yes. The logic is very similar, but Naked Triple requires you to recognize three related cells and three candidates instead of two.
Practise Naked Triples
Open a Medium or Hard Sudoku puzzle, turn on Notes, and look for three cells in the same row, column, or box whose combined candidates contain exactly three numbers.