Intermediate Technique

Obvious Triples

An intermediate technique where three cells can only contain the same three numbers between them, allowing for powerful eliminations.

What Are Obvious Triples?

An Obvious Triple (also called a "Naked Triple") occurs when three cells in the same row, column, or box can only contain the same three numbers between them. These three numbers cannot appear anywhere else in that region.

Key Concept

The three cells don't need to each contain all three numbers as candidates. They just need to collectively contain only those three numbers, with each cell having 2-3 of them.

Cell 1
1, 2
Cell 2
2, 3
Cell 3
1, 3

Example: These three cells form an Obvious Triple with numbers 1, 2, and 3

How to Identify Obvious Triples

The Process

  1. 1 Look for three cells in the same row, column, or box
  2. 2 Check if these cells collectively contain only three different numbers
  3. 3 Verify that each cell has 2-3 candidates from this set
  4. 4 Eliminate these three numbers from all other cells in the same region

Recognition Patterns

Pattern 1:
(1,2) - (2,3) - (1,3)
Pattern 2:
(1,2,3) - (1,2) - (2,3)
Pattern 3:
(1,2,3) - (1,2,3) - (1,2,3)

💡 Pro Tip: Look for cells with 2-3 candidates each, then check if they form a closed group.

Visual Example

In this example, we'll find an Obvious Triple in the top row and use it to eliminate candidates.

Before: Find the Triple

1
3
1
2
2
3
4
5
6
1
2
3
7
8
9
8
9

The first three cells form a triple with numbers 1, 2, and 3 (highlighted in blue)

After: Eliminate Candidates

1
3
1
2
2
3
4
5
6
7
8
9

After eliminating 1, 2, and 3 from other cells in the row, cell 7 becomes an obvious single (7)

When to Use Obvious Triples

Best Situations

  • ✓ When basic techniques aren't yielding progress
  • ✓ In regions with many cells having 2-3 candidates
  • ✓ When you see potential groupings of candidates
  • ✓ In intermediate to hard puzzles

Common Mistakes

  • × Missing triples that don't have all three numbers in each cell
  • × Forgetting to eliminate from ALL other cells in the region
  • × Confusing with Hidden Triples
  • × Not checking all rows, columns, and boxes systematically

Practice Tips

Development Strategy

  1. 1. Master Obvious Pairs first
  2. 2. Practice recognizing the different triple patterns
  3. 3. Always check for eliminations after finding a triple
  4. 4. Combine with other intermediate techniques

Quick Recognition

  • • Look for clusters of 2-3 candidate cells
  • • Count unique numbers across potential triple cells
  • • Check if elimination would create obvious singles
  • • Practice on intermediate difficulty puzzles

Related Techniques

Obvious Pairs

Learn the simpler two-cell version first

Learn technique →

Hidden Triples

The complementary technique to Obvious Triples

Learn technique →

Pointing Pairs

Another intermediate elimination technique

Learn technique →

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