LinkedIn 6x6 Sudoku #340: The Pro-Tips Guide to Cracking the Grid

LinkedIn 6x6 Sudoku #340: Speed-Run Breakdown

You don't speed-run LinkedIn 6x6 Sudoku #340 by guessing; you run it by attacking the most constrained units first. This grid is a masterclass in 2x3 block logic where the solution hinges on spotting a single Hidden Single that unlocks the entire lower half.

The Crucial Square: Row 3, Column 2

The grid finally cracked open at Row 3, Column 2 (the cell containing 3). Before this placement, the middle-left 2x3 block was a deadlock of possibilities. By scanning the column for the number 3, you see it exists in Row 1 and Row 5. Inside the middle-left block, 3 can only fit in that specific cell because Row 3 already has a 6 in Col 1 and a 5 in Col 4, leaving no other valid spot for 3 in that block. Placing 3 here instantly eliminates candidates for 2 and 4 in the same block, creating a cascade of Naked Singles.

Pro-Tip 1: Aggressive Cross-Hatching on 2x3 Blocks

In 6x6 Sudoku, the blocks are 2x3 (two rows, three columns), not the standard 3x3. This changes how you apply Cross-Hatching. Instead of scanning a 3x3 area, pick a single number (like 5) and draw mental lines through rows and columns where it already exists.

Initial Grid Snippet (Top-Left Block):
[?, ?, 5]
[?, 4, ?]

Notice 5 is in Row 1, Col 3. Cross-hatch Row 1. Now look at the Top-Left block: 5 cannot go in Row 1. It must go in Row 2. Since 4 is already in Col 2, 5 drops to Col 1 or Col 3. This rapid elimination is faster than checking every cell individually.

Pro-Tip 2: The 'Difficult Row' is Row 6

Row 6 starts as the most confusing: [?, 6, ?, 2, ?, ?]. It feels empty because it has only two givens. However, this is a Trap Row. The key is to ignore the row and look at the bottom-right 2x3 block. That block contains 1, 4, and 6. By focusing on the block instead of the row, you realize 3, 4, and 5 are missing. The placement of 3 in Row 6, Col 3 is forced because Col 3 already has 5 (Row 1) and 1 (Row 4). This is a classic Hidden Single: the number 3 has only one valid cell in that block.

Pro-Tip 3: Pencil Marks Are Non-Optional

For #340, you cannot speed-run without pencil marks (small candidate notes). In the top-right block, the numbers 1 and 2 form a Pair in two specific cells. Marking them as {1,2} allows you to instantly discard 1 and 2 from other cells in that block, revealing the 6 as a Naked Single. This technique turns a messy grid into a clean, solvable path.

Final Strategy: The 'Re-Scan' Rule

Every time you place a number (like the 3 in Row 3, Col 2), you must re-scan the entire grid. The new number likely creates a new Naked Single in a row you previously ignored. In #340, solving the middle-left block immediately revealed the 4 in Row 4, Col 1, which then unlocked the bottom-left corner. Speed comes from this iterative loop: Place -> Re-scan -> Eliminate -> Place.

Master these three moves on LinkedIn 6x6 Sudoku #340, and you'll clear the grid before your coffee even gets cold.