LinkedIn Mini Sudoku #204: Crack Row 2 First

The Setup: LinkedIn Mini Sudoku #204

This puzzle opens with a deceptive spread of givens—they look scattered, but there's a hidden pattern. You've got anchors in rows 1, 2, and 5, which means the middle section (rows 3-4) will feel skeletal until you isolate the key constraints.

Your Crucial Square: Row 2, Column 5

This is where #204 cracks open. Row 2 only needs two numbers: 1 and 5. You start with 2, 4, and 3 already placed. The moment you realize column 5 already has a 5 (row 3), you're forced to place 1 there—and suddenly row 2 locks into 6-2-5-4-1-3. That's your momentum shift.

Pro-Tip #1: Cross-Hatching the Middle Boxes

Boxes 3 and 4 (the right and middle-right sections) are your bottleneck. Here's the veteran move:

• Scan column 4 for what's missing: you have 4, 3, 5. That means 1, 2, 6 must fit vertically.
• Now look at row 1 in that column—it already needs to avoid 1, 3. Cross that out from box 2.
• This forces 2 into row 3, column 4. Boom—you've unlocked box 3.

Pro-Tip #2: Hidden Singles in Constrained Rows

Row 4 looks brutal—five empty cells. But it's not. It's a hidden single factory:

• Column 1 already has 1, 3—so row 4, column 1 can't be those. Row 4 needs 2, 4, 5, 6.
• Check box 4 (bottom-left): it has 3, 1, 4. Missing 2, 5, 6.
• The intersection? Row 4, column 1 must be 5. That's a hidden single—it's hidden in the box constraint until you filter by row.

The Difficult Row: Row 6 (The Payoff)

Don't solve row 6 directly. It's a cleanup row. By the time you've locked rows 1-5 and columns 1-5, row 6 solves itself through column elimination. This is where speed runners gain time—they never "guess" the final row; they let the grid give it to them.

Technique Breakdown: Why Cross-Hatching Dominates Here

Cross-hatching (scanning rows, then columns, then boxes) is your baseline. But for #204, apply it in this order:

1. Box-first scan: Each box only needs 6 numbers. Smaller search space = faster elimination.
2. Column veto: Once a number lands in one row of a column, that number is dead for the remaining 5 rows in that column.
3. Row confirmation: Only place a number when both its row and column and box agree.

Speed-Run Checkpoint

You should have rows 1-2 locked within 30 seconds. If you don't, you're missing a cross-hatch intersection. Row 4 takes another 45 seconds once you spot the column 1 constraint. The remaining three rows fall in under a minute if you trust the logic.

Why #204 Matters

This grid teaches you that givens aren't random—they cluster in ways that force constraint cascades. The scattered top half pressures the middle, which pressures the bottom. Recognize that pattern, and you'll speed through the next puzzle too.