LinkedIn 6x6 Sudoku #212 Pro-Tips Speed-Run

LinkedIn 6x6 Sudoku #212: Speed-Run Pro-Tips

Grid hits you with 3 in top-left, 4 next to it, then blanks. Row 2 opens with 1 and 5 in the middle. Row 3 kicks off 2, row 4 ends with 3, row 5 has 3 and 6, row 6 closes with 4 and 1. Classic 6x6: rows, columns, 2x3 boxes all need 1-6 unique. Scan fast, strike surgically.

First Strikes: Fill the Obvious

Start top-right box. Row 1 has 3,4; column 6 empty except bottom 1. Cross-hatch for 6: can't hit row 2's 5 or row 3's nothing-yet, but box forces it top-right corner. Boom, 6 slots row1-col6.

Chain it. Now row 2: 1 col2, 5 col5. Column 1 has row1 3, row3 2. Hidden single screams 6 in row2-col1. Box3 confirms, no 6 elsewhere.

Crucial Square: Row 4, Column 2

Here is the breaker. Row 4: blanks everywhere but 5 col3, 3 col6. Early fills pin column 2: row1 5, row2 1, row3 6, row5 3, row6 2. Only 4 fits row4-col2.

That Crucial Square cracks the grid open. Row4 now has 4 col2, 5 col3. Cross-hatch column 4: row1 gets 2 (only spot left after box scan). Row4-col4 hidden single 6. Suddenly row3-col6 5 pops via box naked single.

Difficult Row: Row 6, the Closer

Row 6 fights back: 4 col4, 1 col6. Column 1 empty till now. But upstream fills box6: row4 3 col6 cascades 5 row6-col1. Column 3 cross-hatch nails 6 row6-col3. Hidden pairs in box5 force 2 row6-col2. Rest naked singles: 4,3,1 align.

Pro Techniques in 6x6 Action

• Cross-Hatching: Pencil 1-6 candidates row-by-row, column-by-column in a box. #212 row1 for 2: slashes column hits, leaves one box cell. Faster in 6x6's tight boxes.
• Hidden Singles: Candidate only fits one spot despite multiples. Row2-col1 6: column and box allow nowhere else. Spot these before naked pairs.
• Naked Singles Chain: Fill one, dominoes fall. Post-crucial 4, row4-col1 1 via column, box2 complete.

The Speed-Run Path to Solve

1. Top-right 6 cross-hatch.
2. Row2-col1 6 hidden single.
3. Row3-col2 6 (row scan).
4. Crucial row4-col2 4 (column elimination).
5. Chain: row1-col4 2, row4-col4 6, row3-col6 5.
6. Row6-col1 5, col3 6 cross-hatch.
7. Fillers cascade: boxes complete left, middle fills via pairs.

Under 90 seconds if you nail the crucial square early. Practice cross-hatching these 2x3 boxes; they hide fewer tricks than 3x3. You've got this next time.