100 Large Sudoku Printables - Free! - Free Printable

It looks like you've uploaded a Sudoku puzzle. Let's solve it step by step and explain the logic.

Here is the given Sudoku grid:

```
+-------+-------+-------+
| 1 | 8 | | 6 | 4 | | | | |
| | | 6 | 9 | 8 | | | | 7 |
| 5 | | | | | | | | |
+-------+-------+-------+
| 2 | 6 | 9 | 5 | | | | 8 | |
| | | | 4 | 9 | | | | |
| | 8 | | | 2 | 7 | 9 | 1 | |
+-------+-------+-------+
| 6 | | 4 | | | | | | |
| | 1 | 2 | | | 9 | | | 3 |
| | | | | | | | | |
+-------+-------+-------+
```

We'll denote this as a 9x9 grid with rows and columns numbered from 1 to 9 (top-left to bottom-right). The goal is to fill in the empty cells so that each row, column, and 3x3 box contains digits 1 through 9 exactly once.

---

Step-by-step Solution

Let’s go through logical deductions.

#### First: Fill in easy candidates

We’ll look for cells with only one possible number.

---

Row 1: `1 8 _ | 6 4 _ | _ _ _`
Missing: 2,3,5,7,9

Column 1: `1, _, 5, 2, _, _, 6, _, _` → Missing: 3,4,7,8,9

But let’s start with box 1 (top-left 3x3):

Box 1:
```
1 8 _
_ _ 6
5 _ _
```

Present: 1,5,6,8
Missing: 2,3,4,7,9

Now look at (1,3) — Row 1, Col 3
- Row 1 has: 1,8,?,6,4,?,?,?,? → missing: 2,3,5,7,9
- Column 3: ?,6,?,9,?,?,4,2,? → values: 6,9,4,2 → missing: 1,3,5,7,8
- But 1 already in row 1, so can’t be in (1,3)
- So (1,3) must be from: intersection of {2,3,5,7,9} ∩ {1,3,5,7,8} = {3,5,7}

So possibilities: 3,5,7

Check box 1: (1,3) is in box 1, which has 1,5,6,8 → missing: 2,3,4,7,9

So (1,3): possible 3,5,7 → but 5 is in same box (row 3), so 5 not allowed → eliminate 5

So (1,3): 3 or 7

Try later.

---

Let’s look at (2,9): Row 2, Col 9 = 7

Row 2: `_, _, 6 | 9, 8, _ | _, _, 7`
So missing: 1,2,3,4,5

Column 9: 7, ?, ?, ?, ?, ?, ?, 3, ? → values: 7,3 → missing: 1,2,4,5,6,8,9

Box 3 (top-right):
```
_ _ _
_ _ 7
_ _ _
```
Row 1 col 7–9: ?, ?, ?
Row 2 col 7–9: ?, ?, 7
Row 3 col 7–9: ?, ?, ?

But we know (2,9)=7

Now focus on (3,1)=5, (3,2)=?, (3,3)=?

Row 3: `5, _, _, _, _, _, _, _, _` → missing all except 5

Column 1: 1, ?, 5, 2, ?, ?, 6, ?, ? → present: 1,2,5,6 → missing: 3,4,7,8,9

So (3,1)=5, (4,1)=2, (7,1)=6 → okay.

Now check (4,1)=2, (4,2)=6, (4,3)=9 → so Row 4: `2,6,9 | 5, ?, ?, ?, 8, ?`

Row 4: missing: 1,3,4,7

Column 4: 6,9,?,5,4,?,?,?,? → values: 6,9,5,4 → missing: 1,2,3,7,8

But (4,4)=5 → already placed.

Wait, (4,4)=5 → yes.

Now look at (5,4)=4, (5,5)=9 → Row 5: `?, ?, ?, 4, 9, ?, ?, ?, ?` → missing: 1,2,3,5,6,7,8

Column 5: 4,8,?,?,9,2,?,?,? → values: 4,8,9,2 → missing: 1,3,5,6,7

Now (6,2)=8, (6,5)=2, (6,6)=7, (6,7)=9, (6,8)=1 → Row 6: `?, 8, ?, ?, 2, 7, 9, 1, ?`

So missing: 3,4,5,6

Column 2: 8, ?, 6, 6, ?, 8, ?, 1, ? → wait:

Col 2:
- R1: 8
- R2: ?
- R3: ?
- R4: 6
- R5: ?
- R6: 8 → duplicate! Wait — no, R2 col 2 is blank, R6 col 2 is 8

Wait, R1C2=8, R4C2=6, R6C2=8 → two 8s in column 2? That would be invalid.

Wait — let's double-check original:

Original:
Row 1: 1 8 _ | 6 4 _ | _ _ _
Row 2: _ _ 6 | 9 8 _ | _ _ 7
Row 3: 5 _ _ | _ _ _ | _ _ _
Row 4: 2 6 9 | 5 _ _ | _ 8 _
Row 5: _ _ _ | 4 9 _ | _ _ _
Row 6: _ 8 _ | _ 2 7 | 9 1 _
Row 7: 6 _ 4 | _ _ _ | _ _ _
Row 8: _ 1 2 | _ _ 9 | _ _ 3
Row 9: _ _ _ | _ _ _ | _ _ _

So Col 2:
R1: 8
R2: ?
R3: ?
R4: 6
R5: ?
R6: 8 → two 8s in col 2? R1 and R6 both have 8 → conflict?

Wait — R6C2 is 8 → yes

R1C2 is 8 → yes

So column 2 has two 8s — that’s impossible!

But wait — are they in the same column? Yes — column 2.

R1C2 = 8
R6C2 = 8 → same column → invalid

But that can't be — unless I misread.

Wait: R6 is: `_ 8 _ | _ 2 7 | 9 1 _` → yes, second digit is 8 → R6C2 = 8

R1C2 = 8 → yes

So two 8s in column 2 → contradiction.

But that means either the puzzle is invalid or I made a mistake.

Wait — maybe I copied wrong.

Let me recheck your image description.

You wrote:

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

Wait — that’s not standard format.

Actually, you gave:

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

So let's extract properly.

Let me write full grid with coordinates:

Row 1: [1, 8, _, 6, 4, _, _, _, _]
Row 2: [_, _, 6, 9, 8, _, _, _, 7]
Row 3: [5, _, _, _, _, _, _, _, _]
Row 4: [2, 6, 9, 5, _, _, _, 8, _]
Row 5: [_, _, _, 4, 9, _, _, _, _]
Row 6: [_, 8, _, _, 2, 7, 9, 1, _]
Row 7: [6, _, 4, _, _, _, _, _, _]
Row 8: [_, 1, 2, _, _, 9, _, _, 3]
Row 9: [_, _, _, _, _, _, _, _, _]

Now check Column 2:
- R1: 8
- R2: ?
- R3: ?
- R4: 6
- R5: ?
- R6: 8 ← here!
- R7: ?
- R8: 1
- R9: ?

So R1C2 = 8, R6C2 = 8 → same column, two 8s → invalid

That’s impossible.

Unless there's a typo.

Wait — could it be that R6C2 is not 8?

Look at your input: "6 | | 4 | | | | | | |" — no, wait:

Row 6: `_ 8 _ | _ 2 7 | 9 1 _` → so yes, second cell is 8.

So R6C2 = 8

R1C2 = 8 → conflict.

So the puzzle as given has two 8s in column 2 → unsolvable.

But perhaps you meant something else.

Wait — maybe the numbers are misplaced.

Alternatively, maybe the grid is not aligned correctly.

Let me re-parse your ASCII:

You wrote:

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

So let's list each row:

Row 1: [1, 8, ?, 6, 4, ?, ?, ?, ?]
Row 2: [?, ?, 6, 9, 8, ?, ?, ?, 7]
Row 3: [5, ?, ?, ?, ?, ?, ?, ?, ?]
Row 4: [2, 6, 9, 5, ?, ?, ?, 8, ?]
Row 5: [?, ?, ?, 4, 9, ?, ?, ?, ?]
Row 6: [?, 8, ?, ?, 2, 7, 9, 1, ?]
Row 7: [6, ?, 4, ?, ?, ?, ?, ?, ?]
Row 8: [?, 1, 2, ?, ?, 9, ?, ?, 3]
Row 9: [?, ?, ?, ?, ?, ?, ?, ?, ?]

Now Column 2:
- R1: 8
- R2: ?
- R3: ?
- R4: 6
- R5: ?
- R6: 8 → duplicate 8
- R7: ?
- R8: 1
- R9: ?

So R1C2 = 8, R6C2 = 8 → same column, so invalid

Therefore, the puzzle as given has an error.

Unless you meant R6C2 is not 8?

Wait — in row 6: "_ 8 _ | _ 2 7 | 9 1 _" → so the second number is 8 → R6C2 = 8

But R1C2 = 8 → conflict.

So unless it's a typo, the puzzle is invalid.

Perhaps you intended R6C2 to be something else?

Maybe it's R6C1 = 8? But no, it's written as `_ 8 _` → so second cell.

Alternatively, maybe R1C2 is not 8? But it's clearly written as 8.

Wait — could it be that the first row is: 1, 8, _, 6, 4, _, _, _, _ — yes.

So unless the puzzle is malformed, it's unsolvable due to duplicate 8 in column 2.

But let’s double-check if there's a different interpretation.

Wait — perhaps the bars are not separating columns correctly?

Let me count the separators.

Each row has: | 1 | 8 | | 6 | 4 | | | | |

So that’s 9 cells: positions 1 to 9.

So:
- C1: 1
- C2: 8
- C3: ?
- C4: 6
- C5: 4
- C6: ?
- C7: ?
- C8: ?
- C9: ?

Yes.

Row 6: | | 8 | | | 2 | 7 | 9 | 1 | |

So:
- C1: ?
- C2: 8
- C3: ?
- C4: ?
- C5: 2
- C6: 7
- C7: 9
- C8: 1
- C9: ?

Yes, so C2 has 8 in R1 and R6 → conflict.

So this Sudoku puzzle has an error — two 8s in column 2.

Therefore, it cannot be solved as-is.

But perhaps you meant R6C2 to be something else? Like 3 or 4?

Or maybe R1C2 is not 8?

Wait — maybe the first row is: 1, 8, _, 6, 4, _, _, _, _ — but perhaps the 8 is in a different position?

No, the formatting seems correct.

Alternatively, maybe the puzzle is from a source where the numbers are off.

But based on what you provided, there is a duplicate 8 in column 2, making the puzzle invalid.

---

Conclusion:

The Sudoku puzzle contains an error: two 8s in column 2 (at R1C2 and R6C2), which violates Sudoku rules.

Therefore, the puzzle is unsolvable as given.

Please verify the puzzle and correct the entry — perhaps R6C2 should be a different number (e.g., 3 or 5), or R1C2 is not 8.

If you can provide a corrected version, I’d be happy to solve it.