LinkedIn Mini Sudoku #124 (___ Space) - December 13, 2025: Step-by-Step Solution

Crack today's LinkedIn Mini Sudoku #124, themed ___ Space, published on December 13, 2025. This 6x6 puzzle challenges you to fill the grid so each row, column, and 2x3 box contains digits 1-6 exactly once. Here's the initial grid with clues:

  1 2    
2       
3     5 
4     1 
      6 
  6 4   

We'll solve it step by step using logic like naked singles, process of elimination, and box-line interactions. Follow along to see every empty cell filled with clear reasoning.

Step 1: Analyze Rows, Columns, and Boxes with Most Clues

Start with row 1: Contains 1 (column 3), 2 (column 4). Missing 3,4,5,6. Column 1 has 2 (row 2), 3 (row 3), 4 (row 4)—only spots left are row 1,5,6. Numbers left for column 1: 1,5,6.

Look at top-left 2x3 box (rows 1-2, columns 1-3): Has 1 (row1 col3), 2 (row2 col1), 3 (row3 col1 but outside box). Inside box: missing many, but row1 col1 can't be 1 or 2 (row mates).

Step 2: Fill Easy Naked Singles

Row 5, column 6: Only empty in row 5 (has 6 prefilled). Row 5 must have 1-5 somewhere. But check column 6: has 5 (row3). Wait, refine: Actually, scanning column 6 spots.

Focus on bottom-right box (rows 4-6, columns 4-6): Prefilled 1 (row4 col6), 6 (row5 col6), 4 (row6 col4). Missing 2,3,5.

• Row 6 column 6: Can't be 4 or 6 (row/column mates). Column 6 has 5 (row3)—so possible 1,2,3. But 1 in column 6 (row4). So 2 or 3.

Key insight: Column 2 analysis. Column 2 empty everywhere initially. But later.

Step 3: Column 1 Breakthrough

Column 1: Prefilled 2 (r2), 3 (r3), 4 (r4). Missing 1,5,6 in r1, r5, r6.

• Look at top-left box: r1c1, r1c2, r1c3=1, r2c1=2, r2c2, r2c3.
• Box needs 3,4,5,6 (has 1,2). But 3 in r3c1 (same column as r1c1, outside box).

r1c1 must be 6: Why? In row 1, spots left c1,c2,c5,c6 for 3,4,5,6. But top-left box can't have 3 (column 1 has 3 below). Elimination shows r1c1 only fits 6 (checking possibilities: can't 1,2 row; can't 3 col1; 4,5 possible but later lock).

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

Step 4: Chain Reactions in Row 1 and Top Boxes

Now row 1: 6, ?,1,2,?,?. Missing 3,4,5.

r1c2 = 4: Top-left box now has 6,?,1 (row1), 2 (r2c1). Needs 3,5 (since 4? Wait). Column 2 scan: No prefilled yet. But row1 can't have 3 there (will see). Actually, process: Box needs 3,4,5. r2c2,r2c3 empty. But column 1 logic extends.

r1c5=5, r1c6=3: Row 1 missing 3,4,5. c5 checks column 5 empty so far. But top-right box (r1-2 c4-6): has 2 (r1c4). Elimination locks 5 and 3.

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

Step 5: Row 2 and Middle Progress

Row 2: 2, ?,?,?,?,?. Missing 1,3,4,5,6. Top-left box: now 6,4,1 (r1),2 (r2c1)—needs 3,5 in r2c2,r2c3.

r2c2=5, r2c3=3: Perfect pair—only spots left, and column checks: col2 no 5 yet, col3 has 1 above but ok.

Continue: Top-right box: r1 has 2,5,3; r2 c4,c5,c6 empty. Needs 1,4,6.

r2c4=1, r2c5=6, r2c6=4: Row 2 now fits perfectly, column 6 has 5(r3),3(r1),1(r4)—so 4 ok; eliminations confirm.

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

Step 6: Row 3 and Column Fills

Row 3: 3,?,?,?, ?,5. Missing 1,2,4,6.

Middle-left box (r3-4 c1-3): 3(r3c1),4(r4c1). Needs 1,2,5,6.

r3c2=1: Naked single—check row3 col2 empty peers.

r3c3=2: Follows, box needs it.

r3c4=6, r3c5=4: Middle-right box logic, column 4 has 2(r1),1(r2); etc.

... full row3: 3 1 2 6 4 5

Step 7: Bottom Half Locks In

Row 4: 4, ?,?,?, ?,1. Missing 2,3,5,6.

r4c2=6: Middle-left box now has 3,1,2 (r3),4(r4c1)—needs 5,6. r4c2,c3 spots.

r4c3=5, r4c4=3, r4c5=2: Chain of singles.

Row 5: ?,?,?,?, ?,6. Column 1 now: r1=6,r2=2,r3=3,r4=4—so r5c1=1 (only 1,5 left but 5 elsewhere).

r5c2=2, r5c3=4, r5c4=5, r5c5=3: All singles via row/box/column elimination.

Finally, row 6: ?, ?,6,4, ?,?. Column 1 last r6c1=5. Then r6c2=3, r6c5=1, r6c6=2.

Final Thoughts on LinkedIn Mini Sudoku #124

This puzzle relied on early column 1 fills and box pairs to cascade solutions. Practice naked singles and eliminations for faster solves. Check the solution page to verify your grid. Tomorrow's puzzle drops soon—stay sharp for LinkedIn Games Sudoku mastery!