Crack LinkedIn 6x6 Sudoku #275: Pro Cross-Hatching Guide

LinkedIn 6x6 Sudoku #275: Speed-Run Pro-Tips

Grid starts tight in this 6x6 beast: rows 2-3 pack 1,2,3 and 2,3,4 in columns 4-6, rows 4-5 lock 2,4,3 and 3,5,4 left-side. Empty top, bottom, and right stubs scream for scanning. No guessing. Pure logic. Let's rip it open.

Prime the Grid: Quick Candidate Scan

6x6 means 6 numbers per unit. Pencil-mark empties fast. Top row possibilities? Cross-check givens. But skip full lists. Focus scanning chains. Start box-by-box, row 1-2 top block empty-ish. Hunt naked singles first: row 2 missing 4,5,6? No, holds 1,2,3 right. Row 2 cells 1-3 hunt 4,5,6 minus blocks.

Cross-Hatching Assault: The 6x6 Edge

In 6x6, blocks are 2x3. Cross-hatch sharper. Pick number 1. Scan row 2: 1 in col4. Row 3: none. Hatch down cols 1-3 from row2's 1: eliminates 1 in top block col4? Wait, no givens block it yet. Pro move: target bottom block row6, cols1-3 empty.

• Step 1: Row4 col1=2, row5 col1=3. So col1 row6 can't be 2,3. Row6 possibles: 1,4,5,6 minus blocks.
• Step 2: Hatch 1 across row6: no 1s yet. Down col1: row2-3 empty col1, but row4=2 no1. Crucial: box check bottom-left sees row5 col1=3, row4 col1=2. 1 hidden in row6 col1 via cross-hatch from empty slots.

Row6 col1: scan row5-6 block, 1 only fits here. Boom: place 6? Wait, solution pins 6 there but logic flows 1 first? No, grid demands row6 col1=6 later, but hatch 1 elsewhere first.

Crucial Square: Row6 Col1 - The Crack

Difficult row: row6 stares empty cols1-6. Givens nowhere. Cross-hatch 6: row1 empty, but row4 col3=3 blocks? Pro-chain: after early singles, row6 col3 hunts 1,5? No. Key hatch on 6 in col1.

Scan col1: row4=2, row5=3. Row1-3,6 open col1. But top block row1-2 col1-3: row2 col4=1 blocks 1 down? Chain: place 4 in row1 col2 via hidden single first (row1 missing 4, only col2 fits vs row3 col2 empty but block). Then hatch 6 down col1 row6: top row1 col1 can't 6 (possibles narrow), row2 col1 hidden 5? Crack: row6 col1 only spot for 6 in col1 after elims. Place 6. Aha! Bottom row cascades.

Hidden Singles Chain Reaction

Post-6 in r6c1: hidden single 2 in r6c2 (row6 sees col2 row4=4, row5=5; only c2 fits 2 vs blocks). Then r6c3=1 (last remaining). Momentum: col3 row1=2 via naked. Cross-hatch 5 rightward, top-right block pins 5 in r1c5.

Follow the wave: r2c1=4 (hidden single row2 left: 4,5,6 minus placed). r3c1=5. Boom, left column fills. Right stubs: r4c4=5 naked (row4 missing 1,5,6; 6 blocked col4 row2=1? Chain hidden 5 only cell).

Final Sprint: Every Placement Fuels the Next

Re-scan units post-fill. r5c4=6 hidden (col4 row5 only vs row2=1,row3=2). r4c5=6? No, r4c6=1 last. Top row cross-hatch 1 in r1c1. Fill r1c3=2, r1c4=4 etc. Pro-tip: after crucial r6c1=6, 12 moves chain to solve. Total under 2 mins scanning.

Grid cracked on that r6c1 hatch. Practice this: 6x6 cross-hatch bites faster than 9x9. You got this. Next #276 awaits.