LinkedIn 6x6 Sudoku #229 Pro-Tips Speed-Run

LinkedIn 6x6 Sudoku #229: Speed-Run Pro-Tips

Grab this grid and scan fast: givens at (1,2)=1, (1,5)=3, (2,2)=2, (2,4)=4, (3,4)=5, (4,3)=2, (5,3)=3, (5,5)=4, (6,2)=4, (6,5)=1. In 6x6, blocks are 2x3 rectangles—rows 1-2 cols 1-3 is block 1, and so on. Start with naked singles from givens, then hit cross-hatching to force placements.

Initial Cross-Hatch Blitz: Rows 1-2

Eye row 1: 1 and 3 given, missing 2,4,5,6. Cross-hatch for 2—it's in row 2 col 2, blocks col 1 (row1), col4 (row2, but 4 there), col6 open. But row2 has 2 already, so row1 col6 must be 2. Boom, first placement.

Chain it: now row1 col6=2 blocks row2 col6. Row2 missing 1,3,5,6 (2,4 given). Hatch 1—row1 col2 blocks it, only row2 col1 or col5. But col5 sees row1 col5=3? Wait, refine: col1 open for 1. Actually, pivot to blocks.

Block 1 Breakthrough: Hidden Single for 6

Block 1 (rows1-2, cols1-3): givens 1 at (1,2), 2 at (2,2). Sees no 3,4,5,6 yet. Candidates narrow fast—row1 col1 can't be 1 (row), 3 (col5 sees? No). Cross-hatch 6 in block1: row1 no 6 possible (col6 later 2), row2 col1 and col3. But col3 row2 sees row5 col3=3? Early: hidden single emerges for 6 at row1 col1. Why? Row1 col3 blocked by later logic, but scan columns: col1 row2 can't hold 6 (block2 sees row2 col4=4 influences). Place it—row1 col1=6. Grid cracks open here.

Crucial Square: Row3 Col2 = The Pivot

Here's the crucial square: row3 col2. After initial fills (row1 now 6,1,_,_,3,2), block2 (rows1-2 cols4-6) forces 5 at row2 col5 via elimination—row1 col4=6? Wait, propagate: col5 has row1=3, row5=4, row6=1, so row2 col5=5 (hidden single, can't be 2/6 elsewhere). Row3 col2 hunts 3: col2 has row1=1, row2=2, row6=4, row5 empty but block3 (rows3-4 cols1-3) has row4 col3=2.

Difficult row: row3. Givens only at col4=5. Cross-hatch 3 in row3: possible col1,2,3,6 (col4=5). But block3 can't have 3 at col3 (row4 col3=2 influences pairs), col1 sees later 4. Hidden single pins row3 col2=3. This pivotal placement unlocks block3 entirely—row3 col1=1 (only spot), row3 col3=6, row4 col1=4. Cascade hits row4 col2=5, row3 col6=4.

Hidden Pairs & Propagation: Finish Strong

Now row5: givens col3=3, col5=4. Missing 1,2,5,6. Col1 row5=1 (hidden single, col1 sees row1=6,row2=3,row3=1? Placed row3 col1=1 no—col1: row1=6, row6 empty, but block4 forces 1 at row5 col1 vs row4 col1=4 already? Recheck: post-pivot, col1 fills row2=3 (earlier), row4=4, row6=2 later. Yes, row5 col1=1 clean.

Row6 col6=6 (only missing). Block6 row6 col4=3 (pairs 5/6 elsewhere). Pro-tip: Alternating scans—after row3 col2, re-hatch columns. Col4 row1=6 (only after 4 at row2,5 at row3? Row3 col4=5 given, row5 col5=4 blocks). Full chain: row4 col4=1, row4 col6=3, row5 col2=6, row5 col4=2, row5 col6=5, row6 col1=2, row6 col3=5, row6 col4=3.

Top fills: row1 col3=4, row1 col4=6; row2 col1=3, row2 col3=6, row2 col6=1; row3 col5=2; row4 col5=6, row4 col2=5? Already. Last: row3 col5=2 yes.

Speed-Run Keys for #229

• Cross-hatching early: Row1 col6=2 forces block momentum.
• Hidden singles in blocks: Block1 row1 col1=6, then row3 col2=3 as game-changer.
• Re-scan after each: One placement ripples 3-5 more in 6x6.
• Avoid notes early—trust naked/hidden eyes for sub-90sec solve.

Nail that crucial row3 col2, and #229 folds like clockwork. Practice this flow—you're speed-running next ones.