How to Solve LinkedIn Mini Sudoku #157: Crosswalk

LinkedIn Mini Sudoku puzzles offer a perfect daily mental workout. Today's puzzle, Crosswalk (Question #157), presents a classic 6x6 grid challenge where each row, column, and 2x3 box must contain the digits 1 through 6 exactly once. Let's break down the solving strategy step by step.

Understanding the Starting Position

Before diving into the solution, here's the initial puzzle layout with the given clues:

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

With only 6 clues provided, this puzzle requires systematic logic and the process of elimination to work through each empty cell.

Solving Strategy: Start with Constrained Areas

Following proven 6x6 Sudoku techniques, we begin by focusing on rows, columns, and 2x3 blocks with the most pre-filled numbers. Row 4 has three given digits (6, 2, 4), making it an ideal starting point.

Step 1: Analyze Row 4

Row 4 contains: 6 _ 2 _ 4 _

Missing digits: 1, 3, 5

Now examine the constraints from columns and boxes:

• Position (4,2): Check column 2 and the bottom-left 2x3 box. Column 2 has a 1, so this position cannot be 1. The box already contains 4, so this must be 3 or 5.
• Position (4,4): Column 4 has a 2, limiting options to 1, 3, or 5. Box constraints help narrow further.
• Position (4,6): Column 6 contains 1, 2, 3, so available digits are 4, 5, 6. Since row 4 needs 1, 3, or 5, this position must be 5.

Step 2: Work Through Top-Right Box

The top-right 2x3 box has three clues: 1, 2, 3 in the rightmost column.

Missing digits: 4, 5, 6

Using row and column constraints, we can determine:

• Row 1, position 5: Row 1 ends with 1, so positions 1-5 need 2-6. Column 5 analysis helps identify whether this is 4, 5, or 6.
• Row 2, position 5: Similarly constrained by column 5 and row requirements.
• Row 3, position 5: Row 3 already has 1, 2, 3, so needs 4, 5, 6.

Step 3: Apply Intersection Logic

A powerful technique for 6x6 Sudoku: examine where rows and columns intersect with boxes. When a digit can only appear in certain cells within a box based on row/column constraints, it narrows possibilities significantly.

For example, if column 5 already contains certain digits in other sections, the remaining available digits for cells in column 5 within our target boxes become obvious.

Step 4: Identify Naked Singles

As you fill in more cells, naked singles emerge—cells where only one possible number remains. These are your breakthrough moments in harder puzzles.

Continue analyzing:

• Row 3 with its four given digits severely restricts available positions
• Row 6 (bottom) depends heavily on column constraints from the top
• Row 5 and remaining empty cells benefit from cascading deductions

Step 5: Use Pencil Marks (Mental or Physical)

For cells with multiple possibilities, track candidate numbers. As other cells get solved, eliminate candidates. This systematic elimination eventually reveals the unique solution.

Key Techniques Applied

• Process of Elimination: Remove impossible candidates by checking rows, columns, and boxes
• Box-Line Reduction: When a digit in a box can only appear in one row or column, eliminate it from other cells in that row/column
• Pointing Pairs: Identify when two cells in a box can only contain the same pair of candidates

Why Mini Sudoku Matters

LinkedIn Mini Sudoku puzzles like Crosswalk are excellent for developing logical reasoning skills. The 6x6 format is more manageable than 9x9 grids while still requiring genuine deduction, making them perfect daily brain training.

By mastering these step-by-step approaches, you'll solve increasingly difficult LinkedIn Mini Sudoku puzzles with confidence.

Ready to test your solving skills? Check the full solution and verify your work.