How to Use the Naked Triples Strategy in Sudoku
The Logic Behind a Naked Triple
A Naked Triple occurs when three cells in the same unit (row, column, or block) contain a total of the same three candidates.
Look at this example. The highlighted block contains 3 cells that share exactly 3 numbers.
Therefore, we know with absolute certainty that those three spots are completely locked by these numbers(1, 5, and 8). No other numbers can fit into those cells, and that means 1, 5, and 8 can’t appear in other cells of the unit and can be deleted.
The Golden Rule of Triples (Variations)
A common mistake is thinking that all three cells must look identical (e.g., all containing 1, 5, and 8). In reality, a Naked Triple is valid even if some digits are missing from individual cells. For example, a triple can look like this:
- Cell A: 1 & 5
- Cell B: 5 & 8
- Cell C: 1 & 8
As long as the total pool of candidates across all three cells does not exceed three unique numbers, the strategy works perfectly!
Step-by-Step Elimination
- Scan for matching sets: Look across a unit for three cells that only contain combinations of the same three numbers (in our case: 1, 5, and 8).
- Verify the lock: Ensure no other candidates are hidden inside those three target cells.
- Clean the unit: Go through every other empty cell in that specific row, column, or block, and erase any 1s, 5s, or 8s from their pencil notes.
Where to Apply: Rows, Columns, and Blocks
Just like pairs, triples can be found in any playing zone on the board:
- In a 3×3 Block: Clearing a triple inside a block helps you rapidly shrink the possibilities for the intersecting lines.
- In Lines: Naked Triple can also be applied in a column or row. When you eliminate digits along a full horizontal or vertical line, it frequently exposes a Naked Single in a completely different part of the grid.
Take Your Logic to the Next Level
Spotting Naked Triples requires patience and practice, but it is one of the most rewarding skills to develop. It trains your brain to see groups of cells working together as a single logical unit.
Ready to hunt for triples? Activate your pencil notes, and see how clean you can make your grid!