Step-by-Step Solution to LinkedIn Mini Sudoku #118 (Center Gap) - December 7, 2025

Welcome to the detailed solving guide for LinkedIn Mini Sudoku #118, also known as Center Gap. This 6x6 Sudoku puzzle, published on December 7, 2025, challenges players to fill every row, column, and 2x3 block with digits from 1 to 6 exactly once, starting from a partially completed grid.

The puzzle's key difficulty lies in strategically deciphering which numbers fit in the empty cells without repeating in their rows, columns, or blocks. Let's break down the solving process step-by-step, emphasizing logical deductions over guesswork.

Initial Observations

• The grid is separated into six 2x3 sections, each needing all digits 1 through 6 once.
• Starting clues include a few scattered numbers like 1, 3, 4, 5, and 6 placed in various rows and columns.
• Identifying rows, columns, or boxes with the most clues helps pinpoint where to start.

Step 1: Fill the Obvious Singles

Many cells can be identified by the single possibility method—where only one digit fits without violating Sudoku constraints.

• Row 1: With 3 and 5 already present, examine missing digits (1,2,4,6). Checking columns and the corresponding 2x3 boxes eliminates some options, allowing placement of certain digits.
• Row 2: Starts with '1' and '5'. Analyzing their columns and blocks narrows candidates for empty cells, especially since nearby columns also hold 3, 4, and 6 clues.

Step 2: Use Exclusion Within Columns

For each empty cell, check which numbers are already in the same column and eliminate those from the candidate list.

• For instance, in column 3, encountering '5' and '6' in other rows disallows these numbers from being placed again here.
• Similarly, strip away any digit that conflicts with filled numbers in the cell’s block or row.

Step 3: Analyze Each 2x3 Block (Box)

Each 2x3 box must contain numbers 1 through 6 exactly once. Using this rule helps place elusive numbers.

• The bottom-left box has '3' and '6' placed, so missing numbers must fit into the remaining cells logically.
• Check intersections of row and column constraints within these boxes to deduce exact placements.

Step 4: Identify Naked Singles and Hidden Singles

Naked singles appear when a cell has only one possible digit that fits, while hidden singles occur when a digit only has one possible cell in a row, column, or box.

• Look across rows and columns for digits that can go in only one position.
• For example, if a 2 can only fit in one cell in the middle-right box, place it there.

Step 5: Cross-Referencing Row, Column, and Box Constraints

The puzzle’s name 'Center Gap' hints at the importance of the middle-region intersections.

• Carefully examine the middle 2x3 sections and intersecting rows (3 and 4) and columns (3 and 4). The limited options here critically narrow down possible digits for the empty cells.
• Notice how placing one number can influence available digits for several neighboring cells.

Step 6: Fill by Logical Deduction Until Completion

Systematically applying the above techniques—exclusion, singles identification, and box-row-column intersection checking—gradually reveals all missing numbers.

Every step adds new information that simplifies the remaining puzzle, eventually filling all cells with correct digits.

This puzzle rewards patience and attention to detail. Each deduction is a stepping stone toward the full solution, avoiding guessing and instead relying on pure logic.

For those interested, you can review the full solution afterward to compare steps and solidify your understanding of these techniques.

Enjoy honing your 6x6 Sudoku skills with this carefully crafted challenge!