LinkedIn 6x6 Sudoku #427 Speed-Run Guide

Pro-Tips for LinkedIn 6x6 Sudoku #427

This is a tidy speed-run grid: the opening clues look modest, but the middle boxes quickly become restrictive. Treat each region as a two-row, three-column box, and keep the digits 1 through 6 moving between rows, columns, and boxes.

Start with the obvious pressure points

Row 2 is already carrying 4, 5, 1, 6, leaving only 2 and 3. Column 5 contains a 4 in row 4, while the upper-right box already holds 6 and 3. That combination sharply limits the missing values in the box and makes r2c5 a natural candidate for 2.

Now use cross-hatching: scan across the relevant row and down the relevant column before writing anything. The missing 2 in row 2 cannot sit in column 1, column 3, or column 6, so it is forced into column 5. Row 2 then closes with 3 at r2c2.

The crucial square

The breakthrough is r1c3. Its column already contains 5, 4, 3, 2, 1 elsewhere in the grid, leaving only 6. Place it, and the top-left box becomes much more disciplined: its remaining values can no longer drift freely between the first two rows.

That single placement also changes row 1. With 6 fixed in column 3, the row's candidates compress until r1c5 must be 5, followed by r1c6 = 4. The upper-right box is now complete enough to drive the next pass.

Exploit hidden singles, not guesses

In the middle-left box, the digits 1, 2, and 4 are already anchored. The missing 5 has only one legal position after the column checks, so it becomes a hidden single. This is the sort of move that looks invisible if you inspect rows alone.

Next, the center box tightens around row 4. Its missing values are constrained by the existing 3, 2, and 4, while column 4 already contains 1, 6, and 5. The result is a clean chain that fixes the remaining middle-row placements without trial and error.

Finish with a controlled sweep

Once the central boxes settle, scan in this order: bottom-left box, column 2, bottom-middle box, then the final two columns. Each pass produces a forced placement rather than a speculative one. The lower rows resolve as 3,4,2,5,6,1 and 5,6,1,4,3,2, confirming that every row, column, and box contains the digits 1 through 6 exactly once.

Speed-run lesson: do not chase the most crowded row. Find the cell where a box and a column overlap most aggressively. In #427, that is r1c3; once it falls, the rest of the grid is a disciplined cascade.