Passi risolutivi (36)
Passo 1
Hidden Singles
valore: 5.1
categoria doc: Getting_Started
1 in F2 is last in row/column/box
1 in G9 is last in column/box
6 in A5 is last in row/column/box
6 in J3 is last in row/box
Passo 2
Hidden Singles
valore: 4.9
categoria doc: Getting_Started
5 in G7 is last in row/box
Passo 3
Hidden Singles
valore: 4.7
categoria doc: Getting_Started
9 in G4 is last in row
Passo 4
Naked Singles
valore: 2.3
categoria doc: Getting_Started
Last candidate 2 in A4 changed to solution
Passo 5
Hidden Singles
valore: 4.3
categoria doc: Getting_Started
2 in C7 is last in row/box
Passo 6
Naked Pair
valore: 21
categoria doc: Naked_Candidates
Naked Pair 8/9 on cells {A7|C9} means
- 9 can be removed from B8
- 9 can be removed from B9
Passo 7
Naked Pair
valore: 20.9
categoria doc: Naked_Candidates
Naked Pair 5/6 on cells {B8|B9} means
- 5 can be removed from B2
Last candidate 3 in B2 changed to solution
Passo 8
Hidden Singles
valore: 3.9
categoria doc: Getting_Started
3 in C5 is last in row/box
Passo 9
Hidden Pair
valore: 37.4
categoria doc: Hidden_Candidates
Hidden Pair 1/8 in Row J, on cells {J4|J6}
- removes 3/7 from J4
- removes 4/7 from J6
Passo 10
Hidden Singles
valore: 3.7
categoria doc: Getting_Started
3 in H4 is last in column/box
Passo 11
Naked Pair
valore: 17.9
categoria doc: Naked_Candidates
Naked Pair 1/8 on cells {J4|J6} means
- 8 can be removed from H6
Passo 12
Pointing Pairs
valore: 53.2
categoria doc: Intersection_Removal
Pair: between Box 2 and Col 6:
- 4 can be removed from H6
Passo 13
Rectangle Elimination
valore: 88
categoria doc: Rectangle_Elimination
If +2[D1] then -2[D6] forcing +2[H6] which removes all 2s from box 7, so D1 cannot be 2
Passo 14
Rectangle Elimination
valore: 87.3
categoria doc: Rectangle_Elimination
If +7[E9] then -7[E5] forcing +7[J5] which removes all 7s from box 9, so E9 cannot be 7
Passo 15
X-Cycle
valore: 208
categoria doc: X_Cycles
X-CYCLE on 7 (Discontinuous Alternating Nice Loop, length 6):
+7[B1]-7[B4]+7[F4]-7[E5]+7[E1]-7[B1]
- Contradiction: When B1 is set to 7 the chain implies it cannot be 7 - it can be removed
Last candidate 9 in B1 changed to solution
Passo 16
Hidden Singles
valore: 3.2
categoria doc: Getting_Started
9 in D3 is last in column/box
Passo 17
Hidden Singles
valore: 3
categoria doc: Getting_Started
5 in A3 is last in column
9 in A7 is last in column
Passo 18
Naked Singles
valore: 1.4
categoria doc: Getting_Started
Last candidate 4 in A6 changed to solution
Last candidate 8 in C9 changed to solution
Passo 19
Naked Singles
valore: 1.3
categoria doc: Getting_Started
Last candidate 8 in A2 changed to solution
Passo 20
Hidden Singles
valore: 2.6
categoria doc: Getting_Started
8 in H1 is last in row/column/box
9 in C6 is last in row/column/box
Passo 21
Rectangle Elimination
valore: 61.9
categoria doc: Rectangle_Elimination
If +2[E2] then -2[E5] forcing +2[G5] which removes all 2s from box 7, so E2 cannot be 2
Passo 22
X-Wing
valore: 73.5
categoria doc: X_Wing_Strategy
(Row->Col) 2 taken off D8, based on DH26
Passo 23
Rectangle Elimination
valore: 60.5
categoria doc: Rectangle_Elimination
If +4[E8] then -4[E2] forcing +4[H2] which removes all 4s from box 9, so E8 cannot be 4
Passo 24
3D Medusa
valore: 191.5
categoria doc: 3D_Medusa
(RULE 5): Uncoloured candidate 4 in E1 can see coloured 4 elsewhere and an oppositely coloured 7 in its own cell. It can be removed.
Passo 25
Naked Pair
valore: 11.8
categoria doc: Naked_Candidates
Naked Pair 2/7 on cells {E1|E5} means
- 2 can be removed from E8
Passo 26
Hidden Singles
valore: 2.3
categoria doc: Getting_Started
2 in F8 is last in column/box
Passo 27
Pointing Pairs
valore: 33
categoria doc: Intersection_Removal
Pair: between Box 6 and Col 9:
- 4 can be removed from H9
Passo 28
Y-Wing
valore: 86.9
categoria doc: Y_Wing_Strategy
Y-Wing pattern. Hinge: E8 (5/9), wings E2 H8, therefore
- 4 can be removed from H2
Last candidate 2 in H2 changed to solution
Passo 29
Naked Singles
valore: 1
categoria doc: Getting_Started
Last candidate 5 in D2 changed to solution
Last candidate 7 in H6 changed to solution
Passo 30
Naked Singles
valore: 0.9
categoria doc: Getting_Started
Last candidate 1 in B6 changed to solution
Last candidate 4 in E2 changed to solution
Last candidate 9 in H9 changed to solution
Last candidate 4 in J5 changed to solution
Passo 31
Naked Singles
valore: 0.7
categoria doc: Getting_Started
Last candidate 7 in B4 changed to solution
Last candidate 5 in E9 changed to solution
Last candidate 2 in G5 changed to solution
Last candidate 4 in H8 changed to solution
Last candidate 8 in J6 changed to solution
Last candidate 3 in J8 changed to solution
Passo 32
Naked Singles
valore: 0.5
categoria doc: Getting_Started
Last candidate 6 in B9 changed to solution
Last candidate 2 in D6 changed to solution
Last candidate 6 in D8 changed to solution
Last candidate 7 in E5 changed to solution
Last candidate 9 in E8 changed to solution
Last candidate 8 in F4 changed to solution
Last candidate 1 in J4 changed to solution
Last candidate 7 in J7 changed to solution
Passo 33
Naked Singles
valore: 0.3
categoria doc: Getting_Started
Last candidate 5 in B8 changed to solution
Last candidate 7 in D9 changed to solution
Last candidate 2 in E1 changed to solution
Last candidate 3 in F7 changed to solution
Passo 34
Naked Singles
valore: 0.2
categoria doc: Getting_Started
Last candidate 3 in D1 changed to solution
Last candidate 8 in D7 changed to solution
Last candidate 7 in F3 changed to solution
Last candidate 4 in F9 changed to solution
Passo 35
Naked Singles
valore: 0.1
categoria doc: Getting_Started
Last candidate 4 in C3 changed to solution
Last candidate 6 in F1 changed to solution
Last candidate 4 in G1 changed to solution
Passo 36
Naked Singles
valore: 0
categoria doc: Getting_Started
Last candidate 7 in C1 changed to solution
Last candidate 3 in G3 changed to solution