Beginner Sudoku Tutorial - Learn How to Solve Sudoku Step by Step

Have you ever looked at a Sudoku puzzle and wondered where to even begin? You're not alone. Beginner sudoku puzzles might seem intimidating at first glance, but once you understand the fundamental rules and basic solving techniques, you'll discover that Sudoku is an enjoyable and satisfying puzzle game.

This comprehensive beginner sudoku tutorial will walk you through everything you need to know to solve your first puzzle successfully. We'll start with the absolute basics - explaining what Sudoku is, how the grid works, and what the rules mean in simple terms.

You'll learn fundamental solving techniques like scanning, elimination, and finding single possibilities. We'll break down each concept with clear examples and step-by-step instructions, ensuring you understand not just what to do, but why each technique works.

By the end of this guide, you'll have the confidence and skills to tackle beginner sudoku puzzles independently. Whether you're completely new to Sudoku or have tried it before but got stuck, this tutorial will give you a solid foundation to build upon.

What Is Sudoku? Understanding the Basics

Before diving into solving techniques, let's establish what Sudoku actually is. Sudoku is a logic-based number puzzle that uses a 9x9 grid divided into smaller 3x3 boxes. The goal is simple: fill every empty cell with a number from 1 to 9.

But here's the catch - you can't just place numbers randomly. Each number must follow three strict rules that make Sudoku both challenging and solvable through pure logic.

The Sudoku Grid Structure

Let's break down the Sudoku grid in detail. Picture a large square divided into 81 smaller squares arranged in 9 rows and 9 columns. These rows are numbered from top to bottom (Row 1 through Row 9), and columns are numbered from left to right (Column 1 through Column 9).

Within this large grid, there are 9 smaller boxes, each containing 9 cells arranged in a 3x3 pattern. These boxes are called "regions" or "blocks," and they're arranged in three rows of three boxes each.

To visualize this, imagine the grid divided like a tic-tac-toe board, but instead of 9 large squares, you have 9 boxes, each containing 9 cells. This structure is crucial because the rules apply to rows, columns, AND these 3x3 boxes.

The Three Fundamental Rules of Sudoku

Every valid Sudoku puzzle follows three non-negotiable rules. Understanding these rules is essential because they're the foundation for all solving techniques.

Rule 1: Each row must contain the numbers 1-9 exactly once

This means that in any horizontal row (all 9 cells going from left to right), you must place each number from 1 to 9 exactly one time. You cannot repeat a number in the same row, and you cannot skip a number.

For example, if Row 3 already contains the numbers 1, 2, 3, 4, 5, 6, and 7, then the two empty cells in that row must contain 8 and 9 (in some order). This rule applies to all 9 rows independently.

Rule 2: Each column must contain the numbers 1-9 exactly once

Just like rows, each vertical column (all 9 cells going from top to bottom) must contain each number from 1 to 9 exactly once. No duplicates, no missing numbers.

If Column 5 already has numbers 2, 4, 6, and 8 filled in, then the remaining empty cells in that column must contain 1, 3, 5, 7, and 9. This rule works independently for all 9 columns.

Rule 3: Each 3x3 box must contain the numbers 1-9 exactly once

This is where Sudoku gets interesting. Each of the 9 smaller boxes (the 3x3 regions) must also contain all numbers from 1 to 9 exactly once. This creates overlapping constraints that make the puzzle solvable.

For instance, if the top-left box already contains 1, 2, 3, 4, and 5, then its four empty cells must contain 6, 7, 8, and 9. This rule applies to all 9 boxes.

Why These Rules Matter

These three rules work together to create a puzzle where every number placement affects multiple constraints simultaneously. When you place a number in a cell, it must satisfy all three rules at once - it must be unique in its row, unique in its column, AND unique in its box.

This interconnectedness is what makes Sudoku solvable through logic alone. You don't need to guess - every correct placement can be determined by analyzing which numbers are already present and which numbers are missing.

Understanding Given Numbers and Empty Cells

When you first look at a Sudoku puzzle, you'll see some cells already filled with numbers and others left blank. The filled numbers are called "given numbers," "clues," or "givens." These are the starting point provided by the puzzle creator.

The empty cells are what you need to fill in. A beginner sudoku puzzle typically has 30-40 given numbers, making it easier to solve. More difficult puzzles have fewer given numbers (sometimes as few as 17), which requires more advanced techniques.

How Many Numbers Are Given?

The number of given numbers varies by difficulty level:

• Easy/Beginner puzzles: Usually have 35-40 given numbers
• Medium puzzles: Typically have 28-35 given numbers
• Hard puzzles: Often have 24-28 given numbers
• Expert/Extreme puzzles: May have as few as 17-22 given numbers

For your first puzzles, start with easy or beginner sudoku puzzles that have more given numbers. This gives you more information to work with and makes it easier to learn the basic techniques.

What Given Numbers Tell You

Each given number provides valuable information. It tells you:

1. What number belongs in that specific cell
2. What numbers CANNOT go in other cells in the same row
3. What numbers CANNOT go in other cells in the same column
4. What numbers CANNOT go in other cells in the same box

For example, if you see a "7" in the top-left cell, you immediately know that no other cell in Row 1, Column 1, or the top-left box can contain a 7. This elimination process is the foundation of solving Sudoku.

Your First Solving Technique: Scanning and Elimination

Now that you understand the rules, let's learn your first solving technique. Scanning is the process of systematically looking through rows, columns, and boxes to find cells that can only contain one possible number.

This technique works by using the process of elimination. You look at what numbers are already present in a row, column, or box, and determine which numbers are missing. If only one number is missing and there's only one empty cell, you've found your answer!

Step-by-Step: Finding Your First Number

Let's walk through finding a number using scanning. Here's a simple example:

Step 1: Choose a row, column, or box to examine

Start with a row that has many numbers already filled in. For example, let's say Row 4 has these numbers: 1, 2, 3, 4, 5, 6, 7, and two empty cells.

Step 2: Identify which numbers are missing

Looking at Row 4, you can see it contains 1, 2, 3, 4, 5, 6, and 7. The missing numbers are 8 and 9.

Step 3: Check each empty cell's constraints

Now look at the two empty cells in Row 4. Let's say one empty cell is in Column 2, and the other is in Column 8.

Check Column 2: Does it already contain an 8? Does it already contain a 9? If Column 2 already has an 8, then that cell cannot be 8, so it must be 9.

Check Column 8: Does it already contain an 8? Does it already contain a 9? If Column 8 already has a 9, then that cell cannot be 9, so it must be 8.

Step 4: Place the number

Once you've determined which number goes in which cell, write it in! You've successfully solved your first cell using scanning and elimination.

The Naked Single Technique

The technique we just described is called finding a "naked single" or "sole candidate." This occurs when a cell can only contain one possible number because all other numbers are eliminated by the rules.

A naked single happens when:

• A row, column, or box is missing only one number, AND
• There's only one empty cell in that row, column, or box where that number can go

This is the easiest technique to spot and should be your go-to method when starting out. Always scan for naked singles first before trying more complex techniques.

Understanding Candidates and Pencil Marks

As puzzles get slightly more challenging, you'll encounter cells where multiple numbers are possible. This is where candidates (also called pencil marks) become useful.

Candidates are the small numbers you write in a cell to track which numbers could potentially go there. Instead of guessing, you systematically eliminate candidates until only one remains.

How to Use Candidates

When you look at an empty cell, ask yourself: "Which numbers from 1-9 could possibly go here?" To answer this, check three things:

1. Check the row: Which numbers are already in this row? Those numbers cannot go in this cell.
2. Check the column: Which numbers are already in this column? Those numbers cannot go in this cell.
3. Check the box: Which numbers are already in this 3x3 box? Those numbers cannot go in this cell.

Any number that isn't eliminated by these three checks is a candidate for that cell.

Example: Finding Candidates

Let's say you're looking at an empty cell in Row 3, Column 5, which is in the middle box (the center 3x3 region).

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

Combining all these, the numbers already present are: 1, 2, 3, 4, 5, 6, 7, 8, 9.

Wait - that's all numbers! But remember, we need to check what's actually in each constraint. Let's be more careful:

• Numbers in Row 3: 1, 3, 5, 7, 9 (cannot use these)
• Numbers in Column 5: 2, 4, 6 (cannot use these)
• Numbers in middle box: 1, 2, 3, 8 (cannot use these)

Combining: 1, 2, 3, 4, 5, 6, 7, 8, 9 are all eliminated... but that can't be right if the puzzle is valid. Let me reconsider - some numbers appear in multiple constraints, but we only need to eliminate each number once.

The unique numbers we cannot use are: 1, 2, 3, 4, 5, 6, 7, 8, 9. Actually, if all numbers are eliminated, this means the cell has no valid candidates, which would indicate an error in the puzzle or our analysis.

In a real scenario, you'd find that some numbers are missing from these constraints, and those missing numbers become your candidates.

When to Write Candidates

For beginner sudoku puzzles, you might not need to write candidates for every cell. Start by:

1. Only writing candidates when a cell has 2-3 possible numbers
2. Focusing on cells in rows, columns, or boxes that are nearly complete
3. Updating candidates as you place numbers

As you progress to harder puzzles, you'll need to be more systematic about tracking candidates, but for now, use them as a helpful tool when you get stuck.

The Hidden Single Technique

Once you're comfortable with naked singles, you'll discover another powerful technique: hidden singles. This technique finds numbers that can only go in one specific cell within a row, column, or box, even though that cell might have other candidates too.

How Hidden Singles Work

A hidden single occurs when:

• A number appears as a candidate in only one cell within a row, column, or box
• Even though that cell might have other candidate numbers, this particular number can only go there

This is called "hidden" because the cell itself isn't obviously a single - it might have candidates like 3, 5, 7. But if you look at the row and notice that 5 only appears as a candidate in this one cell, then 5 must go there, regardless of the other candidates.

Finding Hidden Singles: Step by Step

Here's how to find hidden singles:

Step 1: Choose a number to track (1-9)

Pick any number, let's say 5.

Step 2: Check a row for that number

Look at Row 6. Is 5 already placed in Row 6? If yes, move to the next row. If no, check which empty cells in Row 6 could contain 5 (which cells have 5 as a candidate).

Step 3: Count the possibilities

If 5 appears as a candidate in only one cell in Row 6, then 5 must go in that cell! This is a hidden single.

Step 4: Place the number

Even if that cell has other candidates (like 3, 5, 7), you know 5 must go there, so place it and remove the other candidates.

Hidden Singles in Columns and Boxes

The same logic applies to columns and boxes:

• In a column: If a number appears as a candidate in only one cell within that column, it's a hidden single
• In a box: If a number appears as a candidate in only one cell within that 3x3 box, it's a hidden single

Hidden singles are extremely useful because they help you make progress even when naked singles aren't available. Always check for hidden singles when you can't find any obvious placements.

Systematic Solving Approach for Beginners

Now that you know the basic techniques, let's put them together into a systematic approach. Following a methodical process will help you solve beginner sudoku puzzles efficiently and avoid missing obvious placements.

The Beginner's Solving Strategy

Phase 1: Initial Scan (5-10 minutes)

1. Scan all rows for naked singles - look for rows missing only one number
2. Scan all columns for naked singles - look for columns missing only one number
3. Scan all boxes for naked singles - look for boxes missing only one number
4. Place any numbers you find

Phase 2: Candidate Marking (if needed)

5. For rows/columns/boxes that are nearly complete, mark candidates in empty cells
6. Focus on cells with only 2-3 possible numbers initially

Phase 3: Hidden Single Search

7. Go through each number (1-9) and check each row for hidden singles
8. Go through each number (1-9) and check each column for hidden singles
9. Go through each number (1-9) and check each box for hidden singles
10. Place any hidden singles you find

Phase 4: Repeat and Refine

11. After placing numbers, rescan for new naked singles
12. Update your candidate marks as numbers are placed
13. Continue cycling through these techniques until the puzzle is complete

Tips for Efficient Solving

• Work systematically: Don't jump around randomly. Complete your scan of all rows before moving to columns
• Double-check your placements: Before writing a number, verify it doesn't violate any rules
• Stay patient: Beginner puzzles are designed to be solvable. If you're stuck, you might have missed a naked or hidden single
• Take breaks: If you're frustrated, step away and come back with fresh eyes

Common Beginner Mistakes and How to Avoid Them

Learning Sudoku involves making mistakes, but understanding common errors will help you avoid them. Here are the most frequent mistakes beginners make:

Mistake 1: Placing Numbers Without Checking All Constraints

The Error: Seeing that a row needs a 5 and placing it in the first empty cell without checking if the column or box already has a 5.

How to Avoid: Always check three things before placing a number:

1. Is this number already in the row?
2. Is this number already in the column?
3. Is this number already in the box?

Only place the number if all three checks pass.

Mistake 2: Assuming a Number Must Go Somewhere

The Error: Thinking "This box needs a 7, and there's only one empty cell, so 7 must go there" without checking if that cell's row or column already has a 7.

How to Avoid: Remember that every placement must satisfy all three rules simultaneously. A cell might be the only empty cell in a box, but if its row already contains that number, you cannot place it there.

Mistake 3: Forgetting to Update After Placing Numbers

The Error: Placing a number and then continuing to scan without considering how this new number affects other cells.

How to Avoid: After placing each number, pause and think:

• Which row now has this number?
• Which column now has this number?
• Which box now has this number?
• Does this eliminate any candidates in other cells?

Mistake 4: Not Using Candidates When Stuck

The Error: Staring at empty cells trying to guess what goes there instead of systematically tracking possibilities.

How to Avoid: When you can't find any obvious placements, start marking candidates. This will help you spot hidden singles and other patterns.

Mistake 5: Giving Up Too Early

The Error: Thinking a puzzle is impossible when you're actually just missing a hidden single or need to update your candidates.

How to Avoid: Beginner sudoku puzzles are always solvable using basic techniques. If you're stuck:

1. Rescan systematically for naked singles
2. Check for hidden singles you might have missed
3. Update your candidate marks
4. Take a break and return with fresh eyes

Practice Exercise: Solving a Simple Example

Let's work through a simplified example together. This will help you see how the techniques work in practice.

Example Puzzle Setup

Imagine a very simple scenario: You have a row with 8 numbers already filled: 1, 2, 3, 4, 5, 6, 7, 8, and one empty cell.

Step 1: Identify what's missing

The row contains 1, 2, 3, 4, 5, 6, 7, 8. The missing number is 9.

Step 2: Check if 9 can go in the empty cell

• Check the row: 9 is not in this row yet ✓
• Check the column: Does this column already have a 9? Let's say no ✓
• Check the box: Does this box already have a 9? Let's say no ✓

Step 3: Place the number

Since 9 is missing from the row and can go in the empty cell (the column and box don't already have 9), you can confidently place 9 in that cell.

Building Complexity

As you practice, you'll encounter situations where:

• Multiple rows/columns/boxes are nearly complete
• You need to check candidates before placing numbers
• Hidden singles become necessary to make progress

Each puzzle you solve will reinforce these techniques and make them feel more natural.

Moving Beyond Beginner Level

Once you can consistently solve beginner sudoku puzzles, you're ready to learn intermediate techniques. These include:

• Pairs and Triples: When two or three cells in a unit share the same two or three candidates
• Pointing Pairs: When candidates in a box are limited to one row or column
• Box/Line Reduction: Eliminating candidates based on box and line interactions

But don't rush ahead! Master the basics first. Being comfortable with scanning, elimination, naked singles, and hidden singles will make learning advanced techniques much easier.

Tools and Resources for Practice

The best way to improve at beginner sudoku is through regular practice. Here are some recommendations:

• Start with easy puzzles: Many apps and websites offer difficulty ratings. Begin with "Easy" or "Beginner" level puzzles
• Use pencil and paper: Writing candidates physically can help you learn the techniques
• Try digital apps: Many Sudoku apps offer hints and can check your work
• Practice daily: Even 10-15 minutes of practice will help you improve quickly

Remember, every expert was once a beginner. With patience and practice, you'll find yourself solving puzzles faster and more confidently.

Conclusion

Congratulations! You now understand the fundamental concepts of beginner sudoku. You've learned what Sudoku is, how the grid works, the three essential rules, and the basic solving techniques of scanning, elimination, naked singles, and hidden singles.

Remember that solving Sudoku is a skill that improves with practice. Start with easy puzzles that have more given numbers, work systematically through rows, columns, and boxes, and don't be afraid to use candidates when you need them.

The key to success is patience and systematic thinking. Every puzzle is solvable using logic alone - you never need to guess. Trust the process, check your constraints carefully, and celebrate each number you place correctly.

Ready to put your new skills to the test? Download our Sudoku app and start solving beginner puzzles today. With multiple difficulty levels and helpful features, it's the perfect way to practice and improve your Sudoku solving abilities.