... by: newby
9D9, 4(H7,J7), 2((G7,G8)>contradiction therefore 1D9
3D7, 3F3>contradiction
3D7, 3F1, 6(E7, F9)>contradiction therefore 3F8
8C8, 7(E7, F9)>contradiction therefore 8B9
7F9>contrdiction therefore 9F9 solves
... by: Terry
A rational solution is shown in the game log below.
Action: 1 Remove 9 from E3, F3.
Reason: Candidate 9 appears only in sub-column 2-DEF in column 2.
. Therefore, 9 can be removed from E3, F3.
Action: 2 Remove 1 from D7.
Reason: Candidate 1 appears only in sub-column 7-ABC in block 3.
. Therefore, 1 can be removed from D7.
Action: 3 Remove 8 from H6.
Reason: One of the cells C3, C8 must have the value 8.
Therefore, one of the following must be true,
(1) C3 will be 8 in which case E6 will be 8 (in 1 step(s)).
(2) C8 will be 8 in which case H9 will be 8 (in 1 step(s)).
All alternatives result in 8 being removed from H6.
Action: 4 Remove 3 from B3.
Reason: One of the cells H1, H3 must have the value 6.
Therefore, one of the following must be true,
(1) H1 will be 6 in which case 3 will be removed from A3, B3, F3 (in 2 step(s)).
(2) H3 will be 6 in which case B4 will be 3 (in 3 step(s)).
All alternatives result in 3 being removed from B3.
Action: 5 Remove 7 from E6.
Reason: One of the cells D1, D5, D6 must have the value 8.
Therefore, one of the following must be true,
(1) D1 will be 8 in which case E6 will be 8 (in 1 step(s)).
(2) D5 will be 8 in which case E6 will be 5 (in 5 step(s)).
(3) D6 will be 8 in which case E7 will be 7 (in 5 step(s)).
All alternatives result in 7 being removed from E6.
Action: 6 Remove 9 from J7.
Reason: Cell H5 must be one of the values 4, 7, 8.
Therefore, one of the following must be true,
(1) H5 will be 4 in which case J7 will be 4 (in 1 step(s)).
(2) H5 will be 7 in which case 9 will be removed from D7, H7, J7 (in 5 step(s)).
(3) H5 will be 8 in which case 9 will be removed from D7, E7, H7, J7 (in 2 step(s)).
All alternatives result in 9 being removed from J7.
Action: 7 Remove 6 from F1.
Reason: One of the cells F1, F3, F8 must have the value 3.
Therefore, one of the following must be true,
(1) F1 will be 3 in which case F1 will be 3 (in 0 step(s)).
(2) F3 will be 3 in which case F1 will be 5 (in 5 step(s)).
(3) F8 will be 3 in which case H1 will be 6 (in 3 step(s)).
All alternatives result in 6 being removed from F1.
Action: 8 Remove 1 from C3.
Reason: Cell G2 must be one of the values 1, 3, 7.
Therefore, one of the following must be true,
(1) G2 will be 1 in which case A3 will be 1 (in 6 step(s)).
(2) G2 will be 3 in which case G3 will be 1 (in 1 step(s)).
(3) G2 will be 7 in which case 1 will be removed from A3, C3 (in 1 step(s)).
All alternatives result in 1 being removed from C3.
Action: 9 Remove 6 from D1.
Reason: One of the cells H3, H7, H9 must have the value 9.
Therefore, one of the following must be true,
(1) H3 will be 9 in which case H1 will be 6 (in 1 step(s)).
(2) H7 will be 9 in which case D4 will be 6 (in 6 step(s)).
(3) H9 will be 9 in which case D1 will be 8 (in 2 step(s)).
All alternatives result in 6 being removed from D1.
Action: 10 Remove 3 from H1.
Reason: Cell J8 must be one of the values 3, 9.
Therefore, one of the following must be true,
(1) J8 will be 3 in which case F1 will be 3 (in 6 step(s)).
(2) J8 will be 9 in which case H1 will be 6 (in 2 step(s)).
All alternatives result in 3 being removed from H1.
Action: 11 Remove 3 from A1.
Reason: Cell J8 must be one of the values 3, 9.
Therefore, one of the following must be true,
(1) J8 will be 3 in which case F1 will be 3 (in 6 step(s)).
(2) J8 will be 9 in which case A1 will be 7 (in 3 step(s)).
All alternatives result in 3 being removed from A1.
Action: 12 Remove 3 from F3.
Reason: One of the cells H3, J3 must have the value 9.
Therefore, one of the following must be true,
(1) H3 will be 9 in which case 3 will be removed from A3, F3 (in 3 step(s)).
(2) J3 will be 9 in which case F1 will be 3 (in 3 step(s)).
All alternatives result in 3 being removed from F3.
Action: 13 Remove 9 from J9.
Reason: One of the cells A1, B1, F1 must have the value 5.
Therefore, one of the following must be true,
(1) A1 will be 5 in which case J3 will be 9 (in 3 step(s)).
(2) B1 will be 5 in which case J9 will be 5 (in 1 step(s)).
(3) F1 will be 5 in which case J8 will be 9 (in 2 step(s)).
All alternatives result in 9 being removed from J9.
Action: 14 Remove 5 from J4.
Reason: One of the cells G7, J7, J9 must have the value 5.
Therefore, one of the following must be true,
(1) G7 will be 5 in which case E4 will be 5 (in 5 step(s)).
(2) J7 will be 5 in which case J7 will be 5 (in 0 step(s)).
(3) J9 will be 5 in which case J9 will be 5 (in 0 step(s)).
All alternatives result in 5 being removed from J4.
Action: 15 Remove 7 from J4.
Reason: One of the cells F9, H9, J9 must have the value 7.
Therefore, one of the following must be true,
(1) F9 will be 7 in which case E4 will be 7 (in 1 step(s)).
(2) H9 will be 7 in which case J4 will be 3 (in 6 step(s)).
(3) J9 will be 7 in which case J9 will be 7 (in 0 step(s)).
All alternatives result in 7 being removed from J4.
Action: 16 Remove 7 from H7.
Reason: One of the cells C2, C4, C5 must have the value 7.
Therefore, one of the following must be true,
(1) C2 will be 7 in which case H1 will be 7 (in 1 step(s)).
(2) C4 will be 7 in which case E7 will be 7 (in 1 step(s)).
(3) C5 will be 7 in which case 7 will be removed from G7, H7, H9 (in 1 step(s)).
All alternatives result in 7 being removed from H7.
Action: 17 Remove 7 from A2.
Reason: One of the cells H7, H9, J8 must have the value 9.
Therefore, one of the following must be true,
(1) H7 will be 9 in which case A6 will be 7 (in 4 step(s)).
(2) H9 will be 9 in which case A2 will be 6 (in 5 step(s)).
(3) J8 will be 9 in which case A1 will be 7 (in 3 step(s)).
All alternatives result in 7 being removed from A2.
Action: 18 Remove 3 from H3.
Reason: One of the cells H7, H9, J8 must have the value 9.
Therefore, one of the following must be true,
(1) H7 will be 9 in which case H6 will be 3 (in 5 step(s)).
(2) H9 will be 9 in which case A3 will be 3 (in 6 step(s)).
(3) J8 will be 9 in which case H3 will be 9 (in 1 step(s)).
All alternatives result in 3 being removed from H3.
Action: 19 Remove 9 from F8.
Reason: Cell J8 must be one of the values 3, 9.
Therefore, one of the following must be true,
(1) J8 will be 3 in which case F8 will be 6 (in 4 step(s)).
(2) J8 will be 9 in which case J8 will be 9 (in 0 step(s)).
All alternatives result in 9 being removed from F8.
Action: 20 Remove 7 from G5, G6.
Reason: Cell J8 must be one of the values 3, 9.
Therefore, one of the following must be true,
(1) J8 will be 3 in which case G7 will be 7 (in 5 step(s)).
(2) J8 will be 9 in which case G2 will be 7 (in 3 step(s)).
All alternatives result in 7 being removed from G5, G6.
Action: 21 Remove 7 from A5.
Reason: Cell H1 must be one of the values 6, 7.
Therefore, one of the following must be true,
(1) H1 will be 6 in which case A1 will be 7 (in 1 step(s)).
(2) H1 will be 7 in which case J5 will be 7 (in 1 step(s)).
All alternatives result in 7 being removed from A5.
Action: 22 Remove 9 from H9.
Reason: One of the cells G2, G7 must have the value 7.
Therefore, one of the following must be true,
(1) G2 will be 7 in which case H3 will be 9 (in 2 step(s)).
(2) G7 will be 7 in which case H9 will be 8 (in 2 step(s)).
All alternatives result in 9 being removed from H9.
Action: 23 Remove 6 from E7.
Reason: Cell H9 must be one of the values 7, 8.
Therefore, one of the following must be true,
(1) H9 will be 7 in which case E7 will be 7 (in 1 step(s)).
(2) H9 will be 8 in which case 6 will be removed from D7, E7 (in 2 step(s)).
All alternatives result in 6 being removed from E7.
Action: 24 Remove 5 from F6.
Reason: Cell F1 must be one of the values 3, 5.
Therefore, one of the following must be true,
(1) F1 will be 3 in which case G6 will be 5 (in 3 step(s)).
(2) F1 will be 5 in which case F1 will be 5 (in 0 step(s)).
All alternatives result in 5 being removed from F6.
Action: 25 Remove 5 from A1.
Reason: Cell H1 must be one of the values 6, 7.
Therefore, one of the following must be true,
(1) H1 will be 6 in which case A1 will be 7 (in 1 step(s)).
(2) H1 will be 7 in which case C3 will be 5 (in 4 step(s)).
All alternatives result in 5 being removed from A1.
Action: 26 Remove 6 from B1.
Reason: Cell A1 must be one of the values 6, 7.
Therefore, one of the following must be true,
(1) A1 will be 6 in which case A1 will be 6 (in 0 step(s)).
(2) A1 will be 7 in which case H1 will be 6 (in 1 step(s)).
All alternatives result in 6 being removed from B1.
Action: 27 Remove 7 from J7.
Reason: One of the cells H7, J7 must have the value 4.
Therefore, one of the following must be true,
(1) H7 will be 4 in which case E7 will be 7 (in 5 step(s)).
(2) J7 will be 4 in which case J7 will be 4 (in 0 step(s)).
All alternatives result in 7 being removed from J7.
Action: 28 Remove 9 from E7.
Reason: Cell A1 must be one of the values 6, 7.
Therefore, one of the following must be true,
(1) A1 will be 6 in which case H7 will be 9 (in 2 step(s)).
(2) A1 will be 7 in which case E7 will be 7 (in 2 step(s)).
All alternatives result in 9 being removed from E7.
Action: 29 Remove 7 from F5.
Reason: One of the cells B9, J9 must have the value 5.
Therefore, one of the following must be true,
(1) B9 will be 5 in which case F5 will be 2 (in 4 step(s)).
(2) J9 will be 5 in which case J5 will be 7 (in 1 step(s)).
All alternatives result in 7 being removed from F5.
Action: 30 Remove 3 from G8.
Reason: Cell F1 must be one of the values 3, 5.
Therefore, one of the following must be true,
(1) F1 will be 3 in which case J8 will be 3 (in 5 step(s)).
(2) F1 will be 5 in which case F8 will be 3 (in 1 step(s)).
All alternatives result in 3 being removed from G8.
Action: 31 Remove 2 from F8.
Reason: Cell C8 must be one of the values 6, 8.
Therefore, one of the following must be true,
(1) C8 will be 6 in which case F8 will be 3 (in 2 step(s)).
(2) C8 will be 8 in which case G8 will be 2 (in 1 step(s)).
All alternatives result in 2 being removed from F8.
Action: 32 Remove 5 from F3.
Reason: Cell J8 must be one of the values 3, 9.
Therefore, one of the following must be true,
(1) J8 will be 3 in which case E3 will be 5 (in 3 step(s)).
(2) J8 will be 9 in which case F1 will be 5 (in 2 step(s)).
All alternatives result in 5 being removed from F3.
Action: 33 Remove 5 from F5.
Reason: Cell H3 must be one of the values 6, 9.
Therefore, one of the following must be true,
(1) H3 will be 6 in which case F5 will be 1 (in 3 step(s)).
(2) H3 will be 9 in which case F1 will be 5 (in 3 step(s)).
All alternatives result in 5 being removed from F5.
Action: 34 Remove 5 from B1.
Reason: Cell H1 must be one of the values 6, 7.
Therefore, one of the following must be true,
(1) H1 will be 6 in which case F1 will be 5 (in 4 step(s)).
(2) H1 will be 7 in which case B5 will be 5 (in 4 step(s)).
All alternatives result in 5 being removed from B1.
Action: 35 Set F1 to 5.
Reason: Cell F1 is the only cell in column 1 with this candidate (5).
Action: 36 Set F8 to 3.
Reason: Cell F8 is the only cell in row F with this candidate (3).
Action: 37 Set J8 to 9.
Reason: Cell J8 has only one candidate (9).
Action: 38 Set H3 to 9.
Reason: Cell H3 is the only cell in row H with this candidate (9).
Action: 39 Set H1 to 6.
Reason: Cell H1 is the only cell in row H with this candidate (6).
Action: 40 Set A1 to 7.
Reason: Cell A1 has only one candidate (7).
Action: 41 Set G2 to 7.
Reason: Cell G2 is the only cell in column 2 with this candidate (7).
Action: 42 Set E7 to 7.
Reason: Cell E7 is the only cell in column 7 with this candidate (7).
Action: 43 Remove 1 from A3.
Reason: Candidate 1 appears only in sub-column 2-ABC in column 2.
. Therefore, 1 can be removed from A3.
Action: 44 Remove 3 from A3.
Reason: Candidate 3 appears only in sub-column 3-GHJ in block 7.
. Therefore, 3 can be removed from A3.
Action: 45 Remove 5 from A7.
Reason: Cell C2 must be one of the values 1, 6.
Therefore, one of the following must be true,
(1) C2 will be 1 in which case A7 will be 1 (in 1 step(s)).
(2) C2 will be 6 in which case A3 will be 5 (in 1 step(s)).
All alternatives result in 5 being removed from A7.
Action: 46 Remove 9 from D7, B9.
Reason: Cell D9 must be one of the values 1, 9.
Therefore, one of the following must be true,
(1) D9 will be 1 in which case F9 will be 9 (in 1 step(s)).
(2) D9 will be 9 in which case D9 will be 9 (in 0 step(s)).
All alternatives result in 9 being removed from D7, B9.
Action: 47 Remove 5 from B3.
Reason: One of the cells C3, C8 must have the value 8.
Therefore, one of the following must be true,
(1) C3 will be 8 in which case B3 will be 4 (in 1 step(s)).
(2) C8 will be 8 in which case B9 will be 5 (in 1 step(s)).
All alternatives result in 5 being removed from B3.
Action: 48 Remove 6 from D2.
Reason: One of the cells D5, F5 must have the value 2.
Therefore, one of the following must be true,
(1) D5 will be 2 in which case D7 will be 6 (in 1 step(s)).
(2) F5 will be 2 in which case F3 will be 6 (in 1 step(s)).
All alternatives result in 6 being removed from D2.
Action: 49 Remove 6 from C3.
Reason: Cell E8 must be one of the values 2, 6.
Therefore, one of the following must be true,
(1) E8 will be 2 in which case C8 will be 6 (in 1 step(s)).
(2) E8 will be 6 in which case F3 will be 6 (in 1 step(s)).
All alternatives result in 6 being removed from C3.
Action: 50 Remove 6 from E2.
Reason: Cell B1 must be one of the values 3, 8.
Therefore, one of the following must be true,
(1) B1 will be 3 in which case E2 will be 9 (in 2 step(s)).
(2) B1 will be 8 in which case E8 will be 6 (in 2 step(s)).
All alternatives result in 6 being removed from E2.
Action: 51 Remove 6 from A3, B3.
Reason: Candidate 6 appears only in sub-column 2-ABC in column 2.
. Therefore, 6 can be removed from A3, B3.
Action: 52 Set A3 to 5.
Reason: Cell A3 has only one candidate (5).
Action: 53 Remove 5 from B7.
Reason: Cell C2 must be one of the values 1, 6.
Therefore, one of the following must be true,
(1) C2 will be 1 in which case B7 will be 9 (in 2 step(s)).
(2) C2 will be 6 in which case B9 will be 5 (in 2 step(s)).
All alternatives result in 5 being removed from B7.
Action: 54 Remove 5 from B4.
Reason: Cell C3 must be one of the values 4, 8.
Therefore, one of the following must be true,
(1) C3 will be 4 in which case B9 will be 5 (in 2 step(s)).
(2) C3 will be 8 in which case E4 will be 5 (in 2 step(s)).
All alternatives result in 5 being removed from B4.
Action: 55 Remove 6 from E4.
Reason: Cell B9 must be one of the values 5, 8.
Therefore, one of the following must be true,
(1) B9 will be 5 in which case E8 will be 6 (in 2 step(s)).
(2) B9 will be 8 in which case E4 will be 5 (in 2 step(s)).
All alternatives result in 6 being removed from E4.
Action: 56 Set E4 to 5.
Reason: Cell E4 has only one candidate (5).
Action: 57 Set G6 to 5.
Reason: Cell G6 is the only cell in column 6 with this candidate (5).
Action: 58 Remove 8 from D5.
Reason: Candidate 8 appears only in sub-column 5-GHJ in block 8.
. Therefore, 8 can be removed from D5.
Action: 59 Remove 6 from C5.
Reason: Cell B9 must be one of the values 5, 8.
Therefore, one of the following must be true,
(1) B9 will be 5 in which case C5 will be 5 (in 1 step(s)).
(2) B9 will be 8 in which case C8 will be 6 (in 1 step(s)).
All alternatives result in 6 being removed from C5.
Action: 60 Remove 2 from D2.
Reason: One of the cells E3, E8 must have the value 6.
Therefore, one of the following must be true,
(1) E3 will be 6 in which case F3 will be 2 (in 1 step(s)).
(2) E8 will be 6 in which case D7 will be 2 (in 1 step(s)).
All alternatives result in 2 being removed from D2.
Action: 61 Remove 9 from A6.
Reason: Cell D2 must be one of the values 3, 9.
Therefore, one of the following must be true,
(1) D2 will be 3 in which case A6 will be 3 (in 1 step(s)).
(2) D2 will be 9 in which case E6 will be 9 (in 1 step(s)).
All alternatives result in 9 being removed from A6.
... by: ray
#1. Use basic strategies and bi-location/value tool to get working board.
#2. Choose cell B2{3568} - bi-location for 2,tri-location for 5 and 8.
Forcing B2 = 3 ,with basic strategies, gives the solution;other bi-location
1-cell solutions found, by forcing the indicated values and using basic
strategies, are: B4 = 6, D2 = 3, D7 = 6, E3 = 6, H9 = 7.
Some 2-cell solutions found are A2B3 = (6,4), DF1 = (8,5), D6 E4 =
(9,5), G56 =(1,5).