(All the text typed is by blue_239k himself)

$%(Hint : Classic Sudokus are not hard for the beginning but in the middle game. So don't be too glad when you can determine a digit, or soon you will cry.)$

Skill Used :

• X-Wing, Chain (grouped)
• XY-Wing, Chain (grouped)
• XZ-Wing, Chain (grouped)
• YZ-Wing, Chain (grouped)
• XYZ-Wing, Chain (grouped)
• Uniqueness test
• Bivalue Universal Grave
• Multi Colors
• (Dis)continuous Nice Loop (grouped)
• Naked Subsets (grouped)
• Almost Locked Set (XZ, YZ, XY Rules) (grouped)
• AIC (grouped)
• Fish & Sets (grouped) (finned)
• Sue De Coq
• Forcing Chain (Net) Contradiction (Verity)
• other skills below difficulty 2000 (like Empty Rectangle and String-Kites)

---

T1

Difficulty : $\color{orange}{6394}$

Normal Solution Time : >3h

Sudoku :

.---------.---------.---------.
| 6  4  . | .  2  . | .  .  5 |
| 5  .  3 | 9  .  . | 8  .  . |
| .  1  . | .  .  . | .  .  . |
:---------+---------+---------:
| .  3  . | 8  .  . | 4  .  . |
| .  .  . | .  3  . | .  .  . |
| .  .  7 | .  .  1 | .  5  . |
:---------+---------+---------:
| .  .  . | .  .  . | .  9  . |
| .  .  6 | .  .  7 | 5  .  1 |
| 1  .  . | .  5  . | .  7  6 |
'---------'---------'---------'

---

T2

Difficulty : $\color{yellow}{5100}$

Normal Solution Time : >2.5h

Sudoku :

.---------.---------.---------.
| .  1  . | .  7  8 | .  .  . |
| .  .  3 | 6  .  . | .  .  . |
| 4  .  7 | 9  .  . | .  2  8 |
:---------+---------+---------:
| .  .  6 | .  .  . | 1  .  2 |
| .  9  4 | .  2  . | 8  6  . |
| 2  .  1 | .  .  . | 5  .  . |
:---------+---------+---------:
| 1  2  . | .  .  3 | 4  .  5 |
| .  .  . | .  .  9 | 2  .  . |
| .  .  . | 2  1  . | .  8  . |
'---------'---------'---------'

---

T3

Difficulty : $\color{green}{2048}$

Normal Solution Time : ~1h

Sudoku :

.---------.---------.---------.
| .  .  . | 2  .  . | .  6  . |
| 9  3  . | .  7  6 | .  .  . |
| .  2  5 | .  .  . | .  7  4 |
:---------+---------+---------:
| 8  .  3 | 5  .  . | .  .  . |
| .  .  . | 1  4  3 | .  .  . |
| .  .  . | .  .  7 | 2  .  3 |
:---------+---------+---------:
| 3  6  . | .  .  . | 1  5  . |
| .  .  . | 3  1  . | .  9  7 |
| .  1  . | .  .  5 | .  .  . |
'---------'---------'---------'

---

T4

Difficulty : $\color{orange}{6504}$

Normal Solution Time : >3.5h

Sudoku :

.---------.---------.---------.
| 9  8  . | .  1  . | 3  7  . |
| 2  .  . | 7  .  8 | 9  .  . |
| .  5  . | .  .  . | .  .  . |
:---------+---------+---------:
| 8  .  . | 1  .  . | .  6  . |
| .  .  5 | .  .  . | 7  .  . |
| .  4  . | .  .  3 | .  .  5 |
:---------+---------+---------:
| .  .  . | .  .  . | .  2  . |
| .  .  8 | 3  .  2 | .  .  7 |
| .  7  2 | .  8  . | .  1  3 |
'---------'---------'---------'

---

T5

Difficulty : $\color{yellowgreen}{3848}$

Normal Solution Time : >1.5h

Sudoku :

.---------.---------.---------.
| 5  .  1 | 2  .  8 | .  .  . |
| .  .  . | .  .  . | .  .  5 |
| .  .  . | .  9  5 | 1  8  . |
:---------+---------+---------:
| .  .  2 | .  .  . | 3  9  4 |
| .  .  3 | .  7  . | 2  .  . |
| 6  9  5 | .  .  . | 8  .  . |
:---------+---------+---------:
| .  8  6 | 3  5  . | .  .  . |
| 1  .  . | .  .  . | .  .  . |
| .  .  . | 9  .  4 | 6  .  8 |
'---------'---------'---------'

---

T6

Difficulty : $\color{red}{7016}$

Normal Solution Time : >4h

Sudoku :

.---------.---------.---------.
| .  .  . | .  .  9 | .  .  . |
| .  .  5 | 1  4  . | .  .  9 |
| 3  .  . | .  5  . | 8  .  . |
:---------+---------+---------:
| .  3  . | .  .  . | .  6  4 |
| .  5  4 | .  1  . | 7  9  . |
| 7  1  . | .  .  . | .  2  . |
:---------+---------+---------:
| .  .  7 | .  6  . | .  .  1 |
| 1  .  . | .  8  3 | 2  .  . |
| .  .  . | 7  .  . | .  .  . |
'---------'---------'---------'

---

T7

Difficulty : $\color{purple}{12220}$

Normal Solution Time : >7h

Sudoku :

.---------.---------.---------.
| .  .  . | .  .  . | .  5  . |
| 4  .  . | .  .  5 | 6  .  3 |
| 2  9  . | .  .  . | .  4  . |
:---------+---------+---------:
| .  .  9 | .  7  3 | .  .  8 |
| .  .  . | .  8  . | .  .  . |
| 8  .  . | 5  6  . | 9  .  . |
:---------+---------+---------:
| .  4  . | .  .  . | .  6  5 |
| 6  .  3 | 1  .  . | .  .  2 |
| .  7  . | .  .  . | .  .  . |
'---------'---------'---------'

---

T8

Difficulty : $\color{red}{7324}$

Normal Solution Time : >4h

Sudoku :

.---------.---------.---------.
| .  9  . | .  .  4 | 1  6  . |
| .  6  8 | .  2  . | .  .  . |
| 4  .  . | .  .  . | 5  .  . |
:---------+---------+---------:
| .  4  6 | .  .  3 | .  .  . |
| 2  .  . | .  9  . | .  .  1 |
| .  .  . | 7  .  . | 6  2  . |
:---------+---------+---------:
| .  .  7 | .  .  . | .  .  5 |
| .  .  . | .  8  . | 7  4  . |
| .  1  4 | 3  .  . | .  9  . |
'---------'---------'---------'

---

T9

Difficulty : $\color{red}{9032}$

Normal Solution Time : >4.5h

Sudoku :

.---------.---------.---------.
| .  .  1 | 2  .  . | 4  .  . |
| .  2  . | 8  .  . | .  .  1 |
| 7  .  . | .  .  . | .  2  9 |
:---------+---------+---------:
| .  .  5 | 1  3  . | .  .  . |
| .  .  4 | .  2  . | 6  .  . |
| .  .  . | .  8  4 | 1  .  . |
:---------+---------+---------:
| 5  1  . | .  .  . | .  .  6 |
| 6  .  . | .  .  2 | .  5  . |
| .  .  2 | .  .  8 | 3  .  . |
'---------'---------'---------'

---

T10

Difficulty : $\color{yellowgreen}{3020}$

Normal Solution Time : >1.5h

Sudoku :

.---------.---------.---------.
| .  .  1 | 2  .  . | 4  .  . |
| .  2  . | 8  .  . | .  .  1 |
| 7  .  . | .  .  . | .  2  9 |
:---------+---------+---------:
| .  .  5 | 1  3  . | .  .  . |
| .  .  4 | .  2  . | 6  .  . |
| .  .  . | .  8  4 | 1  .  . |
:---------+---------+---------:
| 5  1  . | .  .  . | .  .  6 |
| 6  .  . | .  .  2 | .  5  . |
| .  .  2 | .  .  8 | 3  .  . |
'---------'---------'---------'

---