LinkedIn Mini Sudoku #119 (Hidden X) - Solving the 6x6 Sudoku Puzzle Step-by-Step

Welcome to the detailed solving guide for LinkedIn Mini Sudoku #119, also known as "Hidden X." This 6x6 Sudoku puzzle requires filling each row, column, and 2x3 subgrid with digits 1 through 6 exactly once. Published on December 8, 2025, this puzzle offers a balanced challenge that is ideal for Sudoku enthusiasts looking to hone their deduction skills.

Initial Setup:

• Some cells come prefilled with certain digits, serving as fixed clues.
• The grid is divided into six 2x3 blocks, where each digit from 1 to 6 must appear once.
• The primary strategy involves narrowing possibilities through row, column, and block constraints.

Step-by-step reasoning to fill empty cells:

1. Start with cells having the fewest missing digits in their row, column, or block.

For example, Row 1 has only two missing cells (columns 1 and 6), with digits 1, 4, 5, and 6 mostly present. Checking the missing digits (2 and 3), we can exclude 3 in column 6 as it's already in the corresponding column block and place '2' there, leaving '3' for column 1.

2. Move to Row 2 where two digits are missing in columns 1 and 5. Analyze the digits already in their column and block to find which fit without conflict. Here, placing '5' in column 1 fits due to exclusion from column and box checks, and '1' in column 5 is the remaining valid choice.

3. In Row 3, columns 2 through 5 are empty. With digits 4 and 3 preset at columns 1 and 6, eliminate repeat digits already in the respective columns and boxes to place '2', '5', '1', and '6' accurately. For example, '2' can go in column 2 because of column and box constraints, and so forth for other cells.

4. Row 4 has two preset digits and multiple blanks. Using elimination in columns and blocks, place the missing digits 3, 1, 4, and 2 logically. Digit '3' can be placed in column 2 by excluding existing digits in that row’s box and column.

5. For Row 5’s empty positions, analyze columns and block presence of digits '1' through '6' to place '2' and '5' correctly.

6. Finally, Row 6 has two blanks at columns 1 and 6. Analyze columns and blocks to fill these with remaining digits accurately, such as placing '1' at column 1 and '4' at column 6.

Throughout this process, consistently apply the three fundamental checks: no repeating digits in the same row, column, or 2x3 block.

Key techniques applied:

• Exclusion: Removing digits already present in the same row, column, or box to narrow candidates.
• Single Possibility: Identifying cells where only one digit fits, allowing immediate placement.
• Box-Row-Column Interaction: Using the intersection of possibilities in rows, columns, and boxes to deduce placements.
• Iterative Updates: Each number placed reduces possibilities for others, progressively filling the grid.

This puzzle exemplifies how a clear logical approach focusing on elimination and candidate restriction leads from a challenging partially-filled grid to a complete and correct Sudoku solution.

Try solving it yourself and test your reasoning skills against this intriguing Hidden X puzzle!