LinkedIn Mini Sudoku #135 Fir Tree - December 24, 2025 Step-by-Step Solution

Crack today's LinkedIn Mini Sudoku #135 Fir Tree puzzle from December 24, 2025. This 6x6 grid challenges you to fill rows, columns, and 2x3 boxes with digits 1-6 uniquely. Here's a detailed, logical walkthrough starting from the given clues. We'll label rows 1-6 top to bottom and columns A-F left to right.

Initial Grid Overview

A B C D E F
1 - - - 1 - -
2 - - 4 2 3 -
3 - - - 3 - -
4 - - 6 4 5 -
5 - 3 1 5 4 2
6 - - - 6 - -

Clues: D1=1, C2=4, D2=2, E2=3, D3=3, C4=6, D4=4, E4=5, B5=3, C5=1, D5=5, E5=4, F5=2, D6=6.

Step 1: Fill Row 5 (Easiest Start)

Row 5 has five clues: B5=3, C5=1, D5=5, E5=4, F5=2. Missing A5 and digit 6. A5 must be 6 (only spot left in row, column A empty for 6, bottom-left box needs 6).

A5: 6

Step 2: Bottom-Left Box and Column A

Bottom-left box (A5-F6, but 2x3: A-D5-6, wait no—boxes are 2x3: rows1-2/A-C, rows1-2/D-F; rows3-4/A-C etc. Standard: left boxes A-C, right D-F; top rows1-3? Wait, 6x6 is two rows high? No, 2x3 means 2 rows by 3 cols.

Boxes: Top-left: rows1-2 colsA-C; top-middle: rows1-2 D-F; mid-left rows3-4 A-C; etc. Bottom-left: rows5-6 A-C.

Bottom-left box rows5-6 A-C: A5=6, B5=3, C5=1. Needs 2,4,5. But row6 A-C empty. Column A row6 can't be 6 (A5),3(B5 row),1(C5 col). Wait, better: row5 has all now: 6,3,1,5,4,2.

Now column F row5=2, so F6 can't 2. Look at row6: only D6=6, so A6,B6,C6,E6,F6 need 1-5.

Step 3: Column D Naked Singles

Column D: D1=1, D2=2, D3=3, D4=4, D5=5, D6=6. Perfect! All filled 1-6. No empties left—wait, all were filled or now confirmed? D1 was clue 1, yes all clues or derived.

This locks mid-right box rows3-4 D-F: D3=3,D4=4; E4=5; needs 1,2,6 but row3 D=3, row4 C=6 wait no C is left.

Step 4: Row 2 Right Side

Row 2: C2=4, D2=2, E2=3, F2 empty. Missing 1,5,6. Top-right box rows1-2 D-F: D1=1,D2=2,E2=3. Has 1,2,3; needs 4,5,6. But C2=4 in row2 but C left box. F2 in top-right, so F2 one of 4,5,6 but row2 C=4 so not 4; column F row5=2 no conflict. Wait.

Column E: E2=3, E4=5, E5=4. Can't 3,4,5. Row1 E empty.

Step 5: Focus on Almost-Full Boxes - Bottom Row 6

Bottom-middle box rows5-6 D-F: row5 D5=5,E5=4,F5=2; row6 D6=6. Has 2,4,5,6; needs 1,3. So E6 and F6 are 1 and 3.

Column E: E2=3 so E6 can't 3 → E6=1, F6=3.

E6: 1
F6: 3

Step 6: Column F Chain

Column F now F5=2, F6=3. Row2 F empty, can't 2,3. Top-right box rows1-2 D-F has D1=1,D2=2,E2=3; needs 4,5,6 for F1,F2.

Bottom-right box rows5-6 D-F: D6=6,E6=1,F6=3,F5=2,E5=4,D5=5—all full! Good.

Step 7: Row 4 Fill

Row 4: C4=6, D4=4, E4=5, F4 empty. Missing 1,2,3. Mid-right box rows3-4 D-F: D3=3,D4=4,E4=5; row3 F empty, row4 F empty. Has 3,4,5; needs 1,2,6. But C4=6 in row4 left box.

Column F can't have 2(F5),3(F6),4(E5? no colF). Column F: F5=2,F6=3. Row4 F can't 6(C4 row),4(D4 row),5(E4 row).

Mid-right needs 1,2,6 but 6 where? Row3 F or F4. Column F row4 can't 6? Row4 has 6 already C4 yes can't. So F3=6 (only spot for 6 in box).

F3: 6? Wait no F3 row3 colF.

Wait, mid-right rows3-4 D-F: positions D3=3, E3 empty, F3 empty, D4=4,E4=5,F4 empty. Has 3,4,5; needs 1,2,6.

6 can't go row4 (C4=6 same row), so 6 must be in row3: E3 or F3.

Now column E: E2=3,E4=5,E5=4,E6=1; so E1,E3 empty, can't 1,3,4,5.

Let's find more.

Step 8: Top-Left Box and Pairs

Look at row1: only D1=1, missing 2-6.

Perhaps naked single in row1 column A.

Better systematic: let's place 6s.

Known 6s: A5=6, C4=6, D6=6.

Row1 needs 6: columns A,B,C,E,F possible (D=1).

Top-left box rows1-2 A-C: row2 C2=4, no 6 yet.

Column C: C2=4,C4=6,C5=1; so C1,C3,C6 empty can't 1,4,6.

Row6 C empty, column C can't 1,4,6; row6 has D6=6,F6=3,E6=1 so row6 C can't 1,3,6.

Let's fill row4 F4.

Row4 missing 1,2,3 for A4,B4,F4.

Mid-left box rows3-4 A-C: C4=6, no others. Needs 1-5.

Perhaps column B: only B5=3.

Let's find single for number 2.

Known 2s: D2=2, F5=2.

Look for box with few spots.

Bottom-left box rows5-6 A-C: A5=6,B5=3,C5=1; row6 A6,B6,C6 empty. Has 1,3,6; needs 2,4,5.

So A6,B6,C6 =2,4,5 perm.

Column A: A5=6; no other clues. Can have 2.

Column B: B5=3.

Column C: C5=1,C2=4,C4=6.

Now row6: A6 B6 C6 E6=1 F6=3 D6=6; so missing 2,4,5 for A,B,C exactly matches box.

Is there restriction? Column A row1-4 empty for now.

Let's look at mid-left box rows3-4 A-C: C4=6; others empty. Needs 1,2,3,4,5.

Row5 full: row5 A6 B3 C1 D5 E4 F2.

Now let's try column E full view: E2=3, E4=5, E5=4, E6=1; so missing E1 and E3: must be 2 and 6.

Column E missing 2,6 for E1,E3.

Step 9: Mid-Right Box 6 Placement

Mid-right rows3-4 D-F: D3=3 D4=4 E4=5; empty E3 F3 F4. Has 3,4,5; needs 1,2,6.

E3 is in column E, which needs 2 or 6 there. Perfect.

Row3: D3=3, others empty.

Can 6 go in F4? F4 row4, row4 C4=6 same row no. So 6 not F4.

F3 or E3 for 6.

Now top-right box rows1-2 D-F: D1=1 D2=2 E2=3; empty D nothing wait all D filled, E1 F1 F2.

Top-right empty: E1, F1, F2. Has 1,2,3; needs 4,5,6.

So E1 one of 4,5,6 but column E missing only 2,6 for E1 E3. Intersection: E1 must be 6 (4,5,6 intersect 2,6 =6).

E1: 6

Great! Now column E: E1=6, so E3 must be 2 (remaining).

E3: 2

Step 10: Cascade to F3

Mid-right now E3=2, D3=3,D4=4,E4=5; empty F3 F4. Has 2,3,4,5; needs 1,6.

6 can't F4 (row4 6 already), so F3=6, then F4=1.

F3: 6
F4: 1

Step 11: Row 4 Left Side

Row 4 now C4=6 D4=4 E4=5 F4=1; missing A4 B4: 2,3.

Has 1,4,5,6; missing 2,3 yes.

Bottom-left wait mid-left rows3-4 A-C: C4=6; A4 B4 =2,3 perm.

Column B B5=3, so B4 can't 3 → B4=2, A4=3.

B4: 2
A4: 3

Step 12: Column A Progress

Column A: A4=3, A5=6; row1,2,3,6 empty.

Step 13: Top-Right Remaining

Top-right rows1-2 D-F: D1=1 D2=2 E1=6 E2=3; empty F1 F2. Has 1,2,3,6; needs 4,5.

Row2 C2=4 same row so F2 can't 4 → F2=5, F1=4.

F2: 5
F1: 4

Step 14: Row 1 Right

Row1 now D1=1 E1=6 F1=4; missing A1 B1 C1: 2,3,5.

Step 15: Bottom-Left Row 6

Bottom-left rows5-6 A-C: row5 A6 B3 C1; needs 2,4,5 in A6 B6 C6.

Row6: A6 B6 C6 D6=6 E6=1 F6=3; missing 2,4,5 yes.

Column C: C1 ?, C2=4, C4=6, C5=1, C3?, C6? Can't repeat 1,4,6.

Column C missing 2,3,5 for C1,C3,C6.

Now 2,4,5 for row6 A B C, but column C row6 can't 4 (C2=4 same col), so C6=2 or 5.

Column A missing: known A4=3 A5=6; so 1,2,4,5 for A1,A2,A3,A6.

Step 16: Row 3 Fill

Row 3: D3=3 E3=2 F3=6; missing A3 B3 C3: 1,4,5.

Mid-left rows3-4 A-C: row4 A3=3? A4=3 B4=2 C4=6; row3 A3 B3 C3 empty. Has 2,3,6; needs 1,4,5.

Perfect match for row3 A-C.

Now column B: B4=2 B5=3; row3 B3 one of 1,4,5.

Top-left rows1-2 A-C empty except C2=4.

Column A row4=3 row5=6.

Let's see if single. Perhaps number 5 in column F done: F1=4 F2=5 F3=6 F4=1 F5=2 F6=3—all 1-6 perfect.

Step 17: Place 5s

Known 5s: D5=5 E4=5 F2=5.

Row1 needs 5 in A1 B1 C1 (since D1=1 E1=6 F1=4; missing 2,3,5).

Top-left box rows1-2 A-C: row2 C2=4; row1 A1 B1 C1 will have 2,3,5 but box needs all 1-6, row2 A2 B2 empty too.

Box top-left: positions A1 A2 B1 B2 C1 C2=4. Needs 1,2,3,5,6 (4 present).

Step 18: Column B 5 Impossible

Where can 5 go column B? B4=2 B5=3; possible B1 B2 B3 B6.

B3 in mid-left: needs 1,4,5 yes possible.

B6 in bottom-left needs 2,4,5 yes.

Now row6 needs 2,4,5 A6 B6 C6.

Column B row6 B6 possible 2,4,5 but col B has B4=2 B5=3, so B6 can't 2,3 → B6=4 or 5.

Similarly A6 col A no 4 or5 yet.

C6 col C can't 4,1,6; so C6 2 or5 (from 2,4,5 but no4).

So possible.

Let's look at row1 column C.

Perhaps fill top-middle box? Top-middle rows1-2 D-F full? D1=1 D2=2 E1=6 E2=3 F1=4 F2=5— yes has 1,2,3,4,5,6 perfect!

Step 19: Mid-Top Left? Wait mid-left row3.

Now top-left box: only C2=4 known. Empties A1 A2 B1 B2 C1.

Numbers needed 1,2,3,5,6.

Row1 A1 B1 C1 need 2,3,5 (from row1 missing).

So A1 B1 C1 = perm of 2,3,5.

Thus row2 A2 B2 must be 1,6 (remaining for box, since 4 present, 2,3,5 in row1).

Row2 A2 B2: 1 and 6.

Row2 full: A2 B2 C2=4 D2=2 E2=3 F2=5; yes missing 1,6 perfect.

Step 20: Column A Row2

Column A needs 1,2,4,5 (3,6 placed A4 A5); for A1 A2 A3 A6.

A1 is 2,3 or5 from row1. Intersect with col possible: 2 or5 possible (1,4 also but row1 no1,4).

Row1 missing 2,3,5; col A missing 1,2,4,5 so A1=2 or5 (3 not in col missing? Col missing 1,2,4,5 no 3 yes can't 3 because A4=3).

A4=3 so column A can't have 3 anywhere. Thus A1 can't 3 → A1=2 or 5.

Similarly B1 C1 the other including 3.

Step 21: Bottom-Left 5 and 2

Let's place 1s. Known 1s: D1=1, C5=1, E6=1, F4=1.

Row3 needs 1 in A3 B3 C3 (missing 1,4,5).

Now mid-left rows3-4 A-C: row4 A4=3 B4=2 C4=6; row3 A3= B3 C3=1,4,5.

Column A can't 3,2,6 (A4=3,A5=6, B4=2? No colA). Col A has A4=3 A5=6.

Col B has B4=2 B5=3.

Col C has C2=4 C4=6 C5=1.

For row3 A3: colA can't 3,6; from 1,4,5 all ok except if conflicts.

Now bottom-left needs 2,4,5 in A6 B6 C6.

Col C C6 can't 1,4,6 so from 2,4,5 only 2,5 possible for C6.

Suppose we look at 4 placement column C: col C missing 2,3,5; known no4? C2=4 yes has4.

Col C has4.

Row6 needs2,4,5; C6 can't4 so C6=2 or5.

B6 colB has B4=2 B5=3, missing 1,4,5,6 but row6 B6 from2,4,5 and can't2 so B6=4 or5.

A6 the remaining.

Step 22: Top-Left Row2 1 and6

Row2 A2 B2 =1,6.

Column A A2 one of1,6 but colA A5=6 so A2 can't6 → A2=1, B2=6.

A2: 1
B2: 6

Awesome! Column A now A2=1 A4=3 A5=6; missing A1 A3 A6: 2,4,5.

Step 23: Row1 A1

Row1 A1 B1 C1 =2,3,5.

A1 colA now missing 2,4,5 so A1=2 or5 (not4, and not3).

A1 from 2,5.

Step 24: Column B Update

Column B: B2=6 B4=2 B5=3; missing B1 B3 B6: 1,4,5.

Perfect, row1 B1 from 2,3,5 intersect colB 1,4,5 =5 (only common).

B1=5

Yes! Now row1 A1 C1 missing 2,3 (since B1=5).

A1=2 (only, since 2 or5 but5 taken, and3 impossible col).

A1: 2
C1: 3

Step 25: Top-Left Complete Check

Top-left: A1=2 A2=1 B1=5 B2=6 C1=3 C2=4. Has 1,2,3,4,5,6 yes!

Step 26: Row 3 Left

Row3 A3 B3 C3 =1,4,5.

Column A A1=2 A2=1 A4=3 A5=6; missing A3 A6=4,5.

Column B B1=5 B2=6 B4=2 B5=3; missing B3 B6=1,4.

Column C C1=3 C2=4 C4=6 C5=1; missing C3 C6=2,5.

Now row3 A3 from1,4,5 but colA remaining4,5 so A3=4 or5.

B3 from1,4,5 intersect colB 1,4 =1 or4.

C3 from1,4,5 intersect colC 2,5 wait 2,5 no overlap with1,4,5? 5 yes. C3=5 (only common).

C3: 5

Now row3 A3 B3 =1,4.

A3=4 or5 but now missing1,4 (5 in C3).

1,4 for A3 B3.

A3 colA remaining4,5 but5 taken so A3=4, B3=1.

A3: 4
B3: 1

Step 27: Bottom Row6

Now column A A3=4 so remaining A6=5 (2,4,5 minus2 A1,4 A3).

A6: 5

Row6 A6=5 B6 C6 D6=6 E6=1 F6=3; missing for row 2,4.

Needs all1-6: has1,3,5,6 missing2,4 for B6 C6.

Column B remaining B6=1,4 but1 in B3? B3=1 yes colB has1 now, so B6 can't1 → B6=4.

B6: 4

Then C6=2.

C6: 2

Step 28: Final Checks

All cells filled! Verify columns, rows, boxes.

Row3: A4 B1 C5 D3 E2 F6 all unique.

Column C: C1=3 C2=4 C3=5 C4=6 C5=1 C6=2 perfect.

Column A: A1=2 A2=1 A3=4 A4=3 A5=6 A6=5 perfect.

Column B: B1=5 B2=6 B3=1 B4=2 B5=3 B6=4 perfect.

All boxes match similarly.

Congratulations, puzzle solved! Check the official solution grid to confirm your work. Share your solve time in comments.

Daily LinkedIn Mini Sudoku solutions for Fir Tree #135 Question ID 135. More guides for LinkedIn Games puzzles coming daily.