Nagie Jedynki w Sudoku: Kompletny przewodnik

Czym jest Naked Single?

A naked single is one of the simplest and most reliable techniques in Sudoku. It happens when a cell has only one candidate number left after eliminating all other possibilities based on its row, column, and 3×3 box.

Quick win: Use this technique on our free Sudoku printables (Easy → Master) to build speed and confidence.

Example:

If a cell "sees" 1, 2, 3, 5, 6, 7, 8, and 9 in its row, column, and box, then the only missing digit is 4. That cell must be a 4 - no guessing involved.

Dlaczego Naked Singles mają znaczenie

  • They're usually the first moves you can make in any Sudoku puzzle.
  • They guarantee progress - no chance of being wrong.
  • They act like "low-hanging fruit," clearing the way for harder techniques later.
  • They build confidence for początkującys while still being vital for experienced solvers.

Jak wykryć Naked Single

  1. List candidates for each empty cell.
    Write down the numbers 1–9 that could go there, eliminating those already in the row, column, or box.
  2. Look for cells with only one candidate left.
    If you see something like "{5}" as the only option, you've found a naked single.
  3. Place the number and update the grid.
    Every time you fill a naked single, update other cells' candidates - you'll often reveal new ones.

Nagie Jedynki vs Ukryte Jedynki

It's important not to confuse the two:

  • Naked single: the cell itself has only one candidate left.
  • Hidden single: a number can only appear in one specific cell within a row, column, or box - even if that cell has multiple candidates penciled in.

Think of it like this: naked singles are obvious once candidates are written down; hidden singles are "camouflaged" and require you to scan an entire region. Learn more about Hidden Singles.

Przykład krok po kroku

Let's look at a sample situation:

Row 2: [ | 1 | | | . | | | 6 | ]

Focus on row 2, column 5.

  • Row 2 already contains 1, 6
  • Column 5 already contains 2, 7, 8, 9
  • The 3×3 box already contains 4, 5

What's left? Only 3.
That makes row2-col5 a naked single. Write it in confidently.

Przykład wizualny

  • You have a cell penciled with candidates {1, 4, 5, 9}.
  • After placing a number elsewhere, you realize 1, 4, and 9 are no longer valid in that row.
  • Now the candidates shrink to {5}.
  • Boom - naked single! The cell must be 5.

Strategie szybkiego wykrywania Naked Singles

  1. Cell-by-cell scan
    Go through each empty cell in order and check its candidates.
  2. Prioritize crowded areas
    Rows, columns, or boxes with fewer blanks are more likely to reveal singles.
  3. Digit-focused scanning
    Instead of looking at cells, scan by digit. For example, ask "where can 7 go?" across a row. Sometimes you'll spot a cell where it's the only candidate left.

Common Pitfalls

  • Forgetting to update candidates after placing a number. A missed update can hide naked singles later.
  • Rushing without candidates: while zaawansowany players can sometimes "see" naked singles by eye, początkującys benefit from penciling everything in.
  • Mixing up with hidden singles: if more than one candidate remains, it's not naked.

Practice: Find the Naked Singles

Try this small grid fragment:

Row 7: [ 2 | | | 8 | | | | 5 | ]

In the empty square at row7-col2:

  • Row 7 already has 2, 8, 5
  • Column 2 already has 1, 4, 9
  • Box already has 3, 6

What's left? Only 7. Another naked single.

Why Naked Singles Set the Stage

Think of naked singles as the "on-ramp" to Sudoku solving. They clear the easy numbers first, which often exposes hidden singles, locked candidates, and even zaawansowany moves like naked pairs or X-Wing patterns. Even expert solvers rarely ignore them - they're just too efficient.

Quick Recap

Technique How it Works Difficulty
Naked Single Cell has only one candidate left Początkujący
Hidden Single A digit can only fit in one cell of a unit Początkujący
Locked Candidate A digit's position locks across rows/cols Intermediate

Final Thought

Whenever you're stuck, ask yourself: have I missed any naked singles? More often than not, they're the key to unlocking progress.

Często zadawane pytania

What is a Naked Single in Sudoku?

A naked single is one of the simplest and most reliable techniques in Sudoku. It happens when a cell has only one candidate number left after eliminating all other possibilities based on its row, column, and 3×3 box. If a cell "sees" 1, 2, 3, 5, 6, 7, 8, and 9 in its row, column, and box, then the only missing digit is 4.

How do I spot a Naked Single?

To spot a Naked Single: 1) List candidates for each empty cell by writing down numbers 1–9 that could go there, eliminating those already in the row, column, or box, 2) Look for cells with only one candidate left - if you see something like "{5}" as the only option, you've found a naked single, 3) Place the number and update the grid.

What's the difference between Naked Singles and Hidden Singles?

Naked singles are obvious once candidates are written down - the cell itself has only one candidate left. Hidden singles are "camouflaged" and require scanning an entire region - a number can only appear in one specific cell within a row, column, or box, even if that cell has multiple candidates penciled in.

Why are Naked Singles important?

Naked Singles are important because they're usually the first moves you can make in any Sudoku puzzle, they guarantee progress with no chance of being wrong, they act like "low-hanging fruit" that clears the way for harder techniques later, and they build confidence for początkującys while remaining vital for experienced solvers.

How often should I look for Naked Singles?

You should look for Naked Singles after every placement. Every time you fill a naked single, update other cells' candidates - you'll often reveal new ones. They're the "on-ramp" to Sudoku solving and help clear easy numbers first, which often exposes hidden singles, locked candidates, and zaawansowany moves.

Ready to advance? Check out our kompletnym przewodniku po strategiach for more techniques.

Powiązane strategie

Once you've mastered naked singles, these techniques build naturally:

Ćwicz Naked Singles

Next up: Try the Ukryte Jedynki strategy.

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