LinkedIn 6x6 Sudoku #447 Pro-Tips

Pro-Tips for LinkedIn 6x6 Sudoku #447

This is a six-by-six Sudoku built from six 2x3 boxes. Every row, column, and box must contain 1 through 6 exactly once. The opening is sparse, so do not waste time scanning randomly. Work the intersections.

The Speed-Run Plan

1. Start with the crowded center

The middle columns and central boxes carry the strongest information. The givens 3, 5, 4, 2, 1, 3, and 4 create a useful web of blocked positions. Pencil in candidates only where a row, column, and box all permit them.

For example, the upper-middle box already contains 2, 3, and 5. Its missing digits are 1, 4, and 6. Cross-hatching against the columns quickly narrows those placements, particularly in the top two rows.

2. Hunt hidden singles, not just naked singles

A hidden single is a digit with only one legal home in a row, column, or box, even when that square still has several candidates. In a 6x6 puzzle, this technique is especially efficient because each unit has fewer possible locations.

The lower-middle area is a good example. Once the existing 1, 3, and 4 are accounted for, the remaining candidates become highly restricted. The 6 and 5 placements in the lower rows are not guesses. They are forced by their columns and the surrounding boxes.

The Crucial Square

The breakthrough comes at R1C4. Cross-hatching the upper-middle box leaves 1 as the only viable digit there. Place it, then immediately rescan Row 1, Column 4, and the upper-middle box.

This is the key tactical habit: never make an isolated placement. The moment 1 lands, it removes a candidate from every affected unit. That pressure exposes the remaining values in the top row, including the sequence that resolves as 6, 5, 2, 1, 3, 4.

How the Finish Cascades

With the first row stabilized, the second row becomes a clean candidate exercise. Its given 1 and 2 combine with the newly fixed top row to force the remaining values. The row resolves as 3, 1, 4, 6, 2, 5.

That upper cascade feeds directly into the center. The third row now has only a few legal homes for its missing digits, and the central 3 and 5 act as anchors. Continue by checking each candidate against its box before accepting it.

The lower half is where disciplined rescanning pays off. The fifth row already contains 2, 1, 3, and 4, so its two blanks must be 5 and 6. Column pressure places them in the correct order. The final row then inherits the remaining column values and closes the grid without any trial move.

Veteran Checklist

• Use cross-hatching on the six 2x3 boxes before scanning every row.
• After each placement, rescan the affected row, column, and box.
• Look for hidden singles when a row appears to have several candidates.
• Give priority to squares touched by two or three strong constraints.
• Use R1C4 as the crucial square for this grid, then let the upper rows drive the cascade.

The completed solution is:

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

The lesson from #447 is simple: find the square under the most cross-hatching pressure, place it confidently, and exploit the chain it creates. No guesswork needed.