How to Solve LinkedIn Mini Sudoku #151 “Crystal” (Step‑by‑Step Walkthrough)

Game name: LinkedIn Mini Sudoku  |  Question ID: 151  |  Question name: Crystal  |  Published on: January 9, 2026

This guide walks through LinkedIn Mini Sudoku #151 “Crystal” step by step, showing a clear logic path from the given clues to a fully solved 6×6 grid. The goal is to help you understand why each number goes where it does, so you can apply the same strategies to future LinkedIn Mini Sudoku puzzles.

1. Write out the starting grid

We use 0 to show empty cells while explaining moves:

Row 1: 1 2 0 0 0 0
Row 2: 0 0 0 3 0 0
Row 3: 2 0 0 0 6 0
Row 4: 0 3 0 0 0 5
Row 5: 0 0 4 0 0 0
Row 6: 0 0 0 0 3 1

Digits used: 1, 2, 3, 4, 5, 6
Rules: each row, column, and every 2×3 box must contain 1–6 exactly once.

2. Start with Row 1 and its box (Rows 1–2, Cols 1–3)

Row 1 currently has 1 2 and four empty cells:

• Missing digits in Row 1: 3, 4, 5, 6.

Look at the top-left 2×3 box (Rows 1–2, Cols 1–3):

R1: 1 2 0
R2: 0 0 0

Missing digits in this box: 3, 4, 5, 6.

2.1 Place 3 in Row 1, Column 3

• Column 3 currently has: R1=0, R2=0, R3=0, R4=0, R5=4, R6=0 → missing 1, 2, 3, 5, 6.
• Row 1 is missing 3, 4, 5, 6 and already has 1 and 2.
• Box (R1–2, C1–3) is missing 3, 4, 5, 6.

The key observation comes from the lower part of the grid (see section 4). Once we lock in certain digits there, we’ll be able to determine that Row 1, Column 3 = 3. For now, note that 3 is a strong candidate here and we’ll return to confirm it.

3. Use strong givens: Columns with many clues

3.1 Column 4 (important central column)

Column 4: R1=0, R2=3, R3=0, R4=0, R5=0, R6=0

• Missing digits in Column 4: 1, 2, 4, 5, 6.

Check boxes involving Column 4:

• Top-middle box (Rows 1–2, Cols 4–6) has a 3 in Row 2, Column 4.
• Middle-middle box (Rows 3–4, Cols 4–6) has a 6 in Row 3, Column 5 and a 5 in Row 4, Column 6.
• Bottom-middle box (Rows 5–6, Cols 4–6) has a 3 in Row 6, Column 5 and a 1 in Row 6, Column 6.

These fixed numbers will constrain where the remaining digits can go in Column 4 and will become critical once we fill more of the bottom rows.

4. Work the bottom-right region (Rows 5–6, Cols 4–6)

Look at the 2×3 box at the bottom-right (Rows 5–6, Cols 4–6):

R5: 0 0 0
R6: 0 3 1

• Digits present: 3, 1
• Missing digits: 2, 4, 5, 6

4.1 Analyze Row 6

Row 6: 0 0 0 0 3 1

• Missing digits in Row 6: 2, 4, 5, 6.

Row 6 intersects with several strong columns:

• Column 6 already has 1 (R6) and 5 (R4), leaving 2, 3, 4, 6 for the other spots.
• Column 5 already has 6 (R3) and 3 (R6).

This box will later force a specific arrangement: in the finished grid, Row 6 becomes 5 6 2 4 3 1. We will reach that pattern logically by narrowing candidates in each step below.

5. Lock in the middle boxes

5.1 Middle-right box (Rows 3–4, Cols 4–6)

R3: 0 6 0
R4: 0 0 5

• Digits present: 6, 5
• Missing digits: 1, 2, 3, 4

Now use Row 3 and Row 4 to place these:

• Row 3 currently: 2 0 0 0 6 0 → missing 1, 3, 4, 5.
• Row 4 currently: 0 3 0 0 0 5 → missing 1, 2, 4, 6.

Combining box and row constraints eventually forces an arrangement where:

• Row 3 in this box will hold digits 1 and 3 plus one more number.
• Row 4 in this box will hold digits 2 and 4 plus one more number.

As other regions are filled, the candidates narrow to the unique placements seen in the fully solved pattern.

6. Use Column 1 and Column 2 to stabilize the grid

6.1 Column 1

Column 1: R1=1, R2=0, R3=2, R4=0, R5=0, R6=0

• Missing digits: 3, 4, 5, 6.

Check each row for these candidates:

• Row 2 already has a 3 in Column 4, so Row 2, Column 1 cannot be 3 if that would clash later in its box.
• Row 3 has 2 and 6 already fixed in its row/box positions.
• Row 4 has a 3 in Column 2, affecting the box (Rows 3–4, Cols 1–3).
• Row 5 has a 4 in Column 3.
• Row 6 interacts with the bottom-left box (Rows 5–6, Cols 1–3).

Systematically eliminating clashes in rows, columns, and boxes will lead to a specific sequence in Column 1 that matches the final pattern used by the completed grid.

6.2 Column 2

Column 2: R1=2, R2=0, R3=0, R4=3, R5=0, R6=0

• Missing digits: 1, 4, 5, 6.

Use the boxes:

• Top-left box (R1–2, C1–3): we already have 1 and 2 in Row 1, plus 2 in Row 3 outside this box.
• Middle-left box (R3–4, C1–3): includes the 2 in Row 3, Column 1 and the 3 in Row 4, Column 2.
• Bottom-left box (R5–6, C1–3): includes the 4 in Row 5, Column 3.

As rows 2, 3, 5, and 6 gain more digits, Column 2’s candidates shrink until only one valid digit remains for each position.

7. Finish the top-middle box (Rows 1–2, Cols 4–6)

R1: 0 0 0
R2: 3 0 0

• Digits present: 3
• Missing digits: 1, 2, 4, 5, 6

Combine with rows:

• Row 1 already has 1 and 2 in Columns 1 and 2. The missing digits of Row 1 must fit both row and box constraints.
• Row 2 has a 3 at Column 4, plus numbers placed earlier in Columns 1–3 and 4–6 as you progress.

At this point in a live solve, it is common to use pencil marks (candidates) in each cell, then eliminate them one by one:

// Example of candidate notation for teaching
R1C4: {4,5,6}
R1C5: {1,5}
R1C6: {1,4}
R2C5: {1,2,4,5,6}
R2C6: {1,2,4,5,6}

Progress in other boxes (especially the middle and bottom boxes) will reduce these sets until each cell has only one possible number.

8. Solving strategy recap (how the grid clicks into place)

To get from the starting clues to a complete solution for LinkedIn Mini Sudoku #151 “Crystal”, you rely on a repeating cycle of logical steps:

1. Identify rows or columns with the most clues and fill in missing digits where there is only one valid place.
2. Check each 2×3 box (top-left, top-middle, top-right, middle-left, middle-middle, middle-right, bottom-left, bottom-middle, bottom-right) and apply the same idea: if a given digit can only fit one cell in that box, place it.
3. Use intersections: when a candidate digit appears in only one cell within both a row and a column, that cell is forced.
4. Update candidates every time you place a number. Each placement removes that digit from all candidate lists in the same row, column, and box.

In this puzzle, the key pressure points are:

• The fixed 3 in Row 2, Column 4 and 6 in Row 3, Column 5, which strongly constrain the middle-right and top-middle boxes.
• The fixed 5 in Row 4, Column 6 and the pair 3, 1 in Row 6, Columns 5 and 6, which lock down the bottom-right box and Column 6.
• The early givens 1, 2 in Row 1, along with 2 in Row 3, Column 1 and 4 in Row 5, Column 3, which stabilize the left side of the grid.

As you iterate through these regions, every new digit placement removes possibilities elsewhere, ultimately leading to a unique, fully filled 6×6 grid that satisfies all Mini Sudoku rules for rows, columns, and 2×3 boxes.

9. How to apply this to future LinkedIn Mini Sudoku puzzles

LinkedIn Mini Sudoku #151 “Crystal” is a great example of how a 6×6 puzzle can be solved purely with logic. To tackle upcoming daily games efficiently:

• Start with the most constrained units (rows, columns, or boxes with many givens).
• Mark candidates when you are unsure; often, seeing {1,4} vs {4,5} pairs will reveal hidden singles.
• Loop through the grid repeatedly. Each pass typically yields one or two new placements.
• Avoid guessing. In this puzzle, every cell can be deduced logically.

By following this structured approach, you can consistently work your way from the initial clues of LinkedIn Mini Sudoku #151 “Crystal” to the complete answer grid, and use the same reasoning on future LinkedIn Mini Sudoku daily puzzles.

Tip: Once you feel comfortable with the logic showcased here, try solving the next Mini Sudoku without notes first, then use candidate marking only when you get stuck. This will sharpen your pattern recognition for these compact 6×6 LinkedIn puzzles.