Platon Sudoku · Sudoku Study

Naked Triple · Step-by-step example

Three cells in one row, column, or box contain only three digits between them. Remove those three digits from the other cells in that region.

This course is adapted from Platon Sudoku App. Read the complete example here, then continue learning and practising in the app.

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Recognize the pattern

Three cells in one row, column, or box contain only three digits between them.

How to find it

With candidates visible, compare groups of three cells in one region and count their distinct candidates.

What it allows

Remove those three digits from the other cells in that region.

Avoid the mix-up

The cells do not need identical candidate lists. The union must contain exactly three digits, with no fourth candidate in any selected cell.

Step-by-step example · Row

This example starts from a saved intermediate position. Its candidates include earlier logical eliminations; they are not fresh automatic notes.

Blue: evidence. Green: conclusion. Crossed-out digits: eliminated candidates. R1C1 means row 1, column 1.

Step 1 · Observe the triple

Together, these three cells have only 2, 3, 9 as candidates.

Together, these three cells have only 2, 3, 9 as candidates.

Step 2 · Understand the reservation

Digits cannot repeat in row 5, so these three digits must each occupy one cell.

Digits cannot repeat in row 5, so these three digits must each occupy one cell.

Step 3 · Remove candidates

Remove the marked 2, 3 candidates from other cells in row 5.

Remove the marked 2, 3 candidates from other cells in row 5. R5C7=2, R5C7=3, R5C8=2

What it allows

Remove the marked 2, 3 candidates from other cells in row 5.

Naked Triple · Remove those three digits from the other cells in that region.

Step-by-step example · Column

This example starts from a saved intermediate position. Its candidates include earlier logical eliminations; they are not fresh automatic notes.

Blue: evidence. Green: conclusion. Crossed-out digits: eliminated candidates. R1C1 means row 1, column 1.

Step 1 · Observe the triple

Together, these three cells have only 2, 8, 9 as candidates.

Together, these three cells have only 2, 8, 9 as candidates.

Step 2 · Understand the reservation

Digits cannot repeat in column 8, so these three digits must each occupy one cell.

Digits cannot repeat in column 8, so these three digits must each occupy one cell.

Step 3 · Remove candidates

Remove the marked 8 candidates from other cells in column 8.

Remove the marked 8 candidates from other cells in column 8. R2C8=8, R3C8=8, R6C8=8

What it allows

Remove the marked 8 candidates from other cells in column 8.

Naked Triple · Remove those three digits from the other cells in that region.

Step-by-step example · Box

This example starts from a saved intermediate position. Its candidates include earlier logical eliminations; they are not fresh automatic notes.

Blue: evidence. Green: conclusion. Crossed-out digits: eliminated candidates. R1C1 means row 1, column 1.

Step 1 · Observe the triple

Together, these three cells have only 5, 7, 8 as candidates.

Together, these three cells have only 5, 7, 8 as candidates.

Step 2 · Understand the reservation

Digits cannot repeat in box 1, so these three digits must each occupy one cell.

Digits cannot repeat in box 1, so these three digits must each occupy one cell.

Step 3 · Remove candidates

Remove the marked 5, 8 candidates from other cells in box 1.

Remove the marked 5, 8 candidates from other cells in box 1. R2C1=5, R2C2=5, R3C1=8

What it allows

Remove the marked 5, 8 candidates from other cells in box 1.

Naked Triple · Remove those three digits from the other cells in that region.

Practice

This course is adapted from Platon Sudoku App. Read the complete example here, then continue learning and practising in the app.

View on Google Play