Passi risolutivi (37)
Passo 1
Hidden Singles
valore: 5.7
categoria doc: Getting_Started
4 in B7 is last in row
4 in D6 is last in column/box
5 in J2 is last in row
6 in B8 is last in row
6 in C3 is last in box
6 in F4 is last in row/box
Passo 2
Hidden Singles
valore: 4.9
categoria doc: Getting_Started
4 in C2 is last in row/box
4 in H3 is last in column
5 in E3 is last in column/box
5 in F9 is last in row
6 in J9 is last in column/box
Passo 3
Hidden Singles
valore: 4.5
categoria doc: Getting_Started
4 in F1 is last in row/column/box
Passo 4
Naked Pair
valore: 22
categoria doc: Naked_Candidates
Naked Pair 7/9 on cells {A1|A2} means
- 7 can be removed from A6
- 7/9 can be removed from A8
- 9 can be removed from A9
Passo 5
Pointing Pairs
valore: 64.8
categoria doc: Intersection_Removal
Pair: between Box 5 and Col 5:
- 1 can be removed from C5
- 1 can be removed from G5
- 1 can be removed from H5
Passo 6
Pointing Pairs
valore: 63.5
categoria doc: Intersection_Removal
Pair: between Box 2 and Row C:
- 2 can be removed from C7
- 2 can be removed from C8
- 2 can be removed from C9
Passo 7
Pointing Pairs
valore: 62.7
categoria doc: Intersection_Removal
Pair: between Box 9 and Row G:
- 2 can be removed from G1
- 2 can be removed from G2
Passo 8
Pointing Pairs
valore: 61.5
categoria doc: Intersection_Removal
Pair: between Box 3 and Row C:
- 7 can be removed from C4
- 7 can be removed from C5
- 7 can be removed from C6
Passo 9
Pointing Pairs
valore: 60.7
categoria doc: Intersection_Removal
Pair: between Box 3 and Row C:
- 9 can be removed from C4
- 9 can be removed from C5
Passo 10
Hidden Pair
valore: 39.3
categoria doc: Hidden_Candidates
Hidden Pair 5/9 in Col 5, on cells {B5|G5}
- removes 7 from B5
- removes 3/7/8 from G5
Passo 11
Line/Unit Reduction
valore: 77.6
categoria doc: Intersection_Removal
Line/Box Reduction: 7s in box 5 remove the following in the same box:
- 7 can be removed from E4
- 7 can be removed from E6
Passo 12
Naked Pair
valore: 18.6
categoria doc: Naked_Candidates
Naked Pair 3/8 on cells {A6|E6} means
- 3/8 can be removed from C6
- 3/8 can be removed from G6
- 3/8 can be removed from H6
Last candidate 1 in C6 changed to solution
Passo 13
Naked Singles
valore: 1.8
categoria doc: Getting_Started
Last candidate 6 in H6 changed to solution
Passo 14
Hidden Singles
valore: 3.4
categoria doc: Getting_Started
6 in G1 is last in row/column/box
Passo 15
X-Cycle
valore: 203
categoria doc: X_Cycles
X-CYCLE on 8 (Discontinuous Alternating Nice Loop, length 6):
+8[A8]-8[A6]+8[E6]-8[F5]+8[F8]-8[A8]
- Contradiction: When A8 is set to 8 the chain implies it cannot be 8 - it can be removed
Passo 16
Naked Triple
valore: 65.5
categoria doc: Naked_Candidates
Naked Triple 1/2/3 on cells {A8|G8|J8} means
- 3 can be removed from C8
- 2/3 can be removed from D8
- 2 can be removed from F8
Passo 17
Pointing Pairs
valore: 48.3
categoria doc: Intersection_Removal
Pair: between Box 6 and Col 9:
- 3 can be removed from A9
- 3 can be removed from C9
Passo 18
Rectangle Elimination
valore: 79.8
categoria doc: Rectangle_Elimination
If +3[C4] then -3[J4] forcing +3[J8] which removes all 3s from Box 3, so C4 cannot be 3
Passo 19
Chute Remote Pair
valore: 77.7
categoria doc: Chute_Remote_Pairs
3 cannot be set in the yellow cells {A4,B4,C4} and with the Remote Pair in E6 and H5 it means:
- 8 can be removed from D5
- 8 can be removed from E5
- 8 can be removed from F5
Passo 20
Hidden Singles
valore: 3.1
categoria doc: Getting_Started
8 in F8 is last in row
Passo 21
Pointing Pairs
valore: 43.7
categoria doc: Intersection_Removal
Pair: between Box 5 and Row E:
- 8 can be removed from E1
Passo 22
XY-Chain
valore: 216.6
categoria doc: XY_Chains
length=5, chain ends: D8 and J1
This proves 9 is the solution at one or possibly both ends of the chain
-9[D8]+7[D8]-7[F7]+2[F7]-2[G7]+3[G7]-3[J8]+1[J8]-1[J1]+9[J1]
- 9 can be removed from D1
Passo 23
XY-Chain
valore: 271.8
categoria doc: XY_Chains
length=7, chain ends: A2 and D8
This proves 9 is the solution at one or possibly both ends of the chain
-9[A2]+7[A2]-7[A1]+9[A1]-9[J1]+1[J1]-1[J8]+3[J8]-3[G7]+2[G7]-2[F7]+7[F7]-7[D8]+9[D8]
- 9 can be removed from D2
Passo 24
XY-Chain
valore: 269.2
categoria doc: XY_Chains
length=7, chain ends: C9 and D3
This proves 9 is the solution at one or possibly both ends of the chain
-9[C9]+8[C9]-8[A9]+2[A9]-2[A8]+3[A8]-3[J8]+1[J8]-1[J1]+9[J1]-9[G3]+8[G3]-8[D3]+9[D3]
- 9 can be removed from D9
Passo 25
XY-Chain
valore: 261.3
categoria doc: XY_Chains
length=7. This XY-Chain is continuous and one value in each cell must be the solution, so all off-chain candidates can be removed
-9[G3]+8[G3]-8[D3]+9[D3]-9[D8]+7[D8]-7[F7]+2[F7]-2[G7]+3[G7]-3[J8]+1[J8]-1[J1]+9[J1]
- 3 can be removed from G8
- 1 can be removed from J4
- 9 can be removed from G2
Passo 26
Hidden Singles
valore: 2.7
categoria doc: Getting_Started
9 in A2 is last in column
Passo 27
Naked Singles
valore: 1.3
categoria doc: Getting_Started
Last candidate 7 in A1 changed to solution
Passo 28
Hidden Singles
valore: 2.5
categoria doc: Getting_Started
7 in E5 is last in row
Passo 29
Naked Triple
valore: 47.9
categoria doc: Naked_Candidates
Naked Triple 1/2/3 on cells {G2|G7|G8} means
- 1/3 can be removed from G4
Passo 30
Hidden Singles
valore: 2.3
categoria doc: Getting_Started
1 in H4 is last in column/box
Passo 31
Y-Wing
valore: 88
categoria doc: Y_Wing_Strategy
Y-Wing pattern. Hinge: E1 (2/9), wings D3 H1, therefore
- 8 can be removed from D1
- 8 can be removed from G3
Last candidate 9 in G3 changed to solution
Passo 32
Naked Singles
valore: 0.9
categoria doc: Getting_Started
Last candidate 8 in D3 changed to solution
Last candidate 5 in G5 changed to solution
Last candidate 1 in J1 changed to solution
Passo 33
Naked Singles
valore: 0.7
categoria doc: Getting_Started
Last candidate 9 in B5 changed to solution
Last candidate 2 in D1 changed to solution
Last candidate 3 in G2 changed to solution
Last candidate 7 in G6 changed to solution
Last candidate 3 in J8 changed to solution
Passo 34
Naked Singles
valore: 0.4
categoria doc: Getting_Started
Last candidate 2 in A8 changed to solution
Last candidate 7 in B4 changed to solution
Last candidate 5 in B6 changed to solution
Last candidate 3 in D9 changed to solution
Last candidate 9 in E1 changed to solution
Last candidate 8 in G4 changed to solution
Last candidate 2 in G7 changed to solution
Last candidate 8 in H1 changed to solution
Last candidate 2 in H2 changed to solution
Last candidate 9 in J4 changed to solution
Passo 35
Naked Singles
valore: 0.2
categoria doc: Getting_Started
Last candidate 8 in A9 changed to solution
Last candidate 2 in C4 changed to solution
Last candidate 1 in D5 changed to solution
Last candidate 2 in E9 changed to solution
Last candidate 7 in F7 changed to solution
Last candidate 1 in G8 changed to solution
Last candidate 3 in H5 changed to solution
Passo 36
Naked Singles
valore: 0
categoria doc: Getting_Started
Last candidate 3 in A6 changed to solution
Last candidate 8 in C5 changed to solution
Last candidate 3 in C7 changed to solution
Last candidate 9 in C9 changed to solution
Last candidate 7 in D2 changed to solution
Last candidate 9 in D8 changed to solution
Last candidate 3 in E4 changed to solution
Last candidate 1 in F2 changed to solution
Last candidate 2 in F5 changed to solution
Passo 37
Naked Singles
valore: 0
categoria doc: Getting_Started
Last candidate 7 in C8 changed to solution
Last candidate 8 in E6 changed to solution