Passi risolutivi (35)
Passo 1
Naked Singles
valore: 1
categoria doc: Getting_Started
Last candidate 9 in A3 changed to solution
Passo 2
Hidden Singles
valore: 5.7
categoria doc: Getting_Started
9 in B9 is last in row/box
9 in D1 is last in row
9 in E5 is last in box
Passo 3
Hidden Pair
valore: 52.3
categoria doc: Hidden_Candidates
Hidden Pair 2/8 in Box 2, on cells {A6|B6}
- removes 3 from A6
- removes 3/4/6 from B6
Passo 4
Hidden Pair
valore: 50.3
categoria doc: Hidden_Candidates
Hidden Pair 3/6 in Box 6, on cells {D8|E8}
- removes 1/2/7 from D8
- removes 2/4/5/7 from E8
Passo 5
Naked Pair
valore: 25
categoria doc: Naked_Candidates
Naked Pair 3/6 on cells {D6|D8} means
- 6 can be removed from D3
Last candidate 7 in D3 changed to solution
Passo 6
Hidden Singles
valore: 4.8
categoria doc: Getting_Started
7 in E9 is last in row/box
Passo 7
Hidden Singles
valore: 4.6
categoria doc: Getting_Started
4 in F9 is last in box
Passo 8
Hidden Singles
valore: 4.3
categoria doc: Getting_Started
8 in C9 is last in column
8 in F7 is last in row/box
Passo 9
Hidden Singles
valore: 3.9
categoria doc: Getting_Started
5 in E7 is last in box
8 in A6 is last in row
8 in B1 is last in column/box
8 in J8 is last in row/column/box
Passo 10
Naked Singles
valore: 1.8
categoria doc: Getting_Started
Last candidate 2 in B6 changed to solution
Passo 11
Naked Singles
valore: 1.7
categoria doc: Getting_Started
Last candidate 5 in B8 changed to solution
Passo 12
Hidden Singles
valore: 3.3
categoria doc: Getting_Started
2 in D7 is last in column
5 in C5 is last in row/column/box
5 in F3 is last in column
Passo 13
Naked Singles
valore: 1.5
categoria doc: Getting_Started
Last candidate 1 in D9 changed to solution
Passo 14
Naked Singles
valore: 1.5
categoria doc: Getting_Started
Last candidate 5 in G9 changed to solution
Passo 15
Naked Singles
valore: 1.5
categoria doc: Getting_Started
Last candidate 2 in H9 changed to solution
Passo 16
Hidden Singles
valore: 2.8
categoria doc: Getting_Started
5 in H2 is last in row/column/box
Passo 17
Hidden Singles
valore: 2.7
categoria doc: Getting_Started
9 in H4 is last in row
Passo 18
Naked Pair
valore: 13.1
categoria doc: Naked_Candidates
Naked Pair 1/2 on cells {A8|C8} means
- 1 can be removed from G8
- 1 can be removed from H8
Passo 19
Pointing Pairs
valore: 38.4
categoria doc: Intersection_Removal
Pair: between Box 1 and Col 2:
- 3 can be removed from E2
- 3 can be removed from F2
Passo 20
Pointing Pairs
valore: 38
categoria doc: Intersection_Removal
Pair: between Box 2 and Col 4:
- 4 can be removed from J4
Passo 21
Line/Unit Reduction
valore: 49
categoria doc: Intersection_Removal
Line/Box Reduction: 4s in box 7 remove the following in the same box:
- 4 can be removed from G1
- 4 can be removed from G2
- 4 can be removed from H1
Passo 22
X-Cycle
valore: 181.6
categoria doc: X_Cycles
X-CYCLE on 6 (Discontinuous Alternating Nice Loop, length 8):
+6[C4]-6[C3]+6[E3]-6[E8]+6[D8]-6[D6]+6[F4]-6[C4]
- Contradiction: When C4 is set to 6 the chain implies it cannot be 6 - it can be removed
Passo 23
Pointing Pairs
valore: 35.9
categoria doc: Intersection_Removal
Pair: between Box 2 and Row B:
- 6 can be removed from B2
Passo 24
XY-Chain
valore: 224.8
categoria doc: XY_Chains
length=7, chain ends: E8 and C3
This proves 6 is the solution at one or possibly both ends of the chain
-6[E8]+3[E8]-3[D8]+6[D8]-6[D6]+3[D6]-3[F4]+6[F4]-6[J4]+1[J4]-1[C4]+4[C4]-4[C3]+6[C3]
- 6 can be removed from E3
Last candidate 4 in E3 changed to solution
Passo 25
Naked Singles
valore: 1.1
categoria doc: Getting_Started
Last candidate 6 in C3 changed to solution
Passo 26
XY-Chain
valore: 219.5
categoria doc: XY_Chains
length=8, chain ends: A5 and J4
This proves 1 is the solution at one or possibly both ends of the chain
-1[A5]+3[A5]-3[A2]+2[A2]-2[E2]+6[E2]-6[E8]+3[E8]-3[D8]+6[D8]-6[D6]+3[D6]-3[F4]+6[F4]-6[J4]+1[J4]
- 1 can be removed from C4
- 1 can be removed from H5
- 1 can be removed from J5
Last candidate 4 in C4 changed to solution
Passo 27
Hidden Singles
valore: 1.8
categoria doc: Getting_Started
1 in A5 is last in column/box
1 in C8 is last in row
1 in H1 is last in row
1 in J4 is last in column/box
4 in B2 is last in row/box
4 in J1 is last in column
Passo 28
Naked Singles
valore: 0.6
categoria doc: Getting_Started
Last candidate 2 in A8 changed to solution
Last candidate 9 in J7 changed to solution
Passo 29
Naked Singles
valore: 0.6
categoria doc: Getting_Started
Last candidate 3 in A2 changed to solution
Last candidate 1 in G7 changed to solution
Passo 30
Hidden Singles
valore: 1.1
categoria doc: Getting_Started
1 in F2 is last in row/column/box
9 in G2 is last in row/column/box
Passo 31
Bi-value Universal Grave
valore: 30.5
categoria doc: BUG
BUG+1 found in E1, 6 must be the solution
All other incomplete cells contain two candidates apart from E1. Other candidates in E1 would lead to zero, two or more solutions so they can be removed.
Last candidate 6 in E1 changed to solution
Passo 32
Naked Singles
valore: 0.3
categoria doc: Getting_Started
Last candidate 2 in E2 changed to solution
Last candidate 3 in E8 changed to solution
Last candidate 3 in F1 changed to solution
Last candidate 7 in G1 changed to solution
Passo 33
Naked Singles
valore: 0.2
categoria doc: Getting_Started
Last candidate 2 in C1 changed to solution
Last candidate 7 in C2 changed to solution
Last candidate 6 in D8 changed to solution
Last candidate 6 in F4 changed to solution
Last candidate 4 in G8 changed to solution
Last candidate 6 in J2 changed to solution
Passo 34
Naked Singles
valore: 0
categoria doc: Getting_Started
Last candidate 3 in B4 changed to solution
Last candidate 3 in D6 changed to solution
Last candidate 6 in G6 changed to solution
Last candidate 7 in H8 changed to solution
Last candidate 7 in J5 changed to solution
Passo 35
Naked Singles
valore: 0
categoria doc: Getting_Started
Last candidate 6 in B5 changed to solution
Last candidate 3 in H5 changed to solution
Last candidate 4 in H6 changed to solution