LinkedIn 6x6 Sudoku #429 Speed-Run Guide

The Speed-Run View

LinkedIn 6x6 Sudoku #429 uses six 3-wide by 2-tall boxes, with every row, column, and box requiring the digits 1 through 6. The fastest approach is not to chase isolated blanks. Build pressure across the grid, then let the constrained areas force the next move.

Pro-Tips for #429

1. Start with the crowded edges

The top-left box already contains 1, 2 in its first row and 2, 4 in its second. That immediately limits the missing digits to 3, 5, 6. Cross-hatching from the lower rows and columns narrows these placements, creating an early route into the upper-middle section.

Do the same on the right side. The second row ends with 1, 3, while the fourth row ends with 2, 5. Those paired clues sharply restrict the remaining values in the two right-hand boxes. Treat those boxes as launch points, not as separate problems.

2. Use cross-hatching aggressively

In a 6x6 grid, cross-hatching is especially powerful because each row and column removes a large fraction of the candidates. For example, once a row already contains 1, 2, and 3, its empty cells can only draw from 4, 5, 6. Check those three digits against the columns and the relevant 3x2 box before writing anything.

The key speed-run habit is to scan both directions: row first, then column, then box. A candidate that survives two checks often disappears on the third.

3. The crucial square

The breakthrough comes in the upper-middle box, especially at the square in row 1, column 3. Once the surrounding row and column restrictions are applied, that square is forced to 3. This is the crucial square because it removes 3 from the rest of the box and stabilizes the first row.

That placement triggers a clean sequence: the remaining top-row values resolve into 5, 4, 6, and the neighboring columns gain sharply reduced candidate lists. The grid stops behaving like a collection of guesses and starts behaving like a chain reaction.

4. Hunt hidden singles, not just naked singles

After the top row settles, inspect each box for a digit that has only one legal location, even if that cell still has several pencil-mark candidates. This is a hidden single.

In #429, the middle-left region is a good example. The existing 2, 4, 3, 1 placements leave a narrow route for 5 and 6. Column restrictions then identify the only valid home for one of them. Place it, rescan the row, and the other follows without guesswork.

5. The difficult row

Row 4 is the row to watch. Its fixed 2 and 5 make it look partially solved, but the remaining four cells initially compete among several candidates. Do not force it early. Instead, solve the boxes feeding into columns 1 through 4.

Once those columns receive their missing values, row 4 compresses to 6, 3, 1, 4 in its open positions. This is the second major aha moment: the difficult row was never meant to be solved independently. It was a receiver for deductions generated elsewhere.

How the Final Answer Emerges

With the upper-left box stabilized and the central boxes narrowed, the lower-left clues 3, 1 become decisive. Cross-hatching places 4 and 6 around them, leaving the lower rows with only a few legal arrangements.

The final right-side sweep is straightforward. The last two columns already contain complementary clues, so each missing digit has one remaining position in its row or box. Completing those placements produces the finished grid:

1 2 3 5 4 6
4 5 6 2 1 3
2 4 5 3 6 1
6 3 1 4 2 5
3 1 4 6 5 2
5 6 2 1 3 4

The tactical lesson from #429 is simple: secure the crucial square, exploit hidden singles, and let the difficult row wait until the columns have done the heavy lifting. No speculative branching is required.