print out EXAMPLE 1 puzzle grid
SUDOKU:
3 worked examples
a step-by-step analysis
of three ‘hard’ grids
|
EXAMPLE 1 EXAMPLE 2 EXAMPLE 3 |
If you have difficulty with the more challenging sudoku puzzle grids, but are determined to win through, then you may find this page helpful. Initially, you could print out a copy of any of the puzzle grids and see how you do without the notes. Normal sudoku rules apply. Each square of the puzzle grid carries a reference number (01 to 81) in the top right corner. Cells are marked by a vertically aligned label in the first square. Rows are assumed counted from the left, and columns from the top. The sweep pattern used in solving is generally 1 to 9, top left to bottom right. |
print out EXAMPLE 1 puzzle grid
| digit | context | square | because |
| 2 | Cell 2 | 05 |
04 blocked (58); 06 blocked (33) 13 blocked (58); 14 taken; 15 blocked (33) 22 taken; 23 blocked (21); 24 taken |
| 2 | Cell 4 | 37 |
28 blocked (33); 29 blocked (33/65); 30 blocked (21/33) 38 taken; 39 blocked (21) 46 taken; 47 blocked (65); 48 taken |
| 4 | Cell 4 | 47 |
28 blocked (36); 29 blocked (36); 30 blocked (36/57) 37 taken; 38 taken; 39 blocked (57) 46 taken; 48 taken |
| 8 | Cell 1 | 03 |
01 taken; 02 blocked (38) 10 blocked (17); 11 taken; 12 blocked (17) 19 blocked (22); 20 blocked (22/38); 21 taken |
| 8 | Cell 6 | 54 |
34 taken; 35 blocked (17); 36 taken 43 blocked (38/61); 44 taken; 45 blocked (38) 52 blocked (61); 53 blocked (17) |
| 8 | Cell 5 | 32 |
31 blocked (22); 33 taken 40 blocked (22/38); 41 blocked (38); 42 blocked (38) 49 taken; 50 blocked (54); 51 blocked (54) |
| 5 | Cell 1 | 02 |
01 taken; 03 taken 10 blocked (14); 11 taken; 12 blocked (14) 19 blocked (25); 20 blocked (25); 21 taken |
| 5 | Cell 7 | 55 |
in Cell 8: 58 taken; 59 blocked (14); 60 taken 68 taken 76 blocked (81); 77 blocked (14/81); 78 blocked (81) therefore: the 5 for Cell 8 must go 67 or 69 - whichever, the rest of Row 8 is blocked in Cell 7: 56 blocked (02); 57 taken 64 blocked (67 or 69); 65 taken; 66 blocked (67 or 69) 73 blocked (81); 74 blocked (02/81); 75 blocked (81) |
| 9 | Row 7 | 59 |
55 taken; 56 blocked (11); 57 taken 58 taken; 60 taken 61 taken; 62 blocked (71); 63 blocked (71) |
| 9 | Cell 3 | 27 |
in Cell 2: 05 taken 13 blocked (11); 14 taken; 15 blocked (11) 22 taken; 23 blocked (59); 24 taken therefore: the 9 for Cell 2 must go 04 or 06 - whichever, the rest of Row 1 is blocked in Cell 3: 07 blocked (04 or 06); 08 blocked (04 or 06/71); 09 blocked (04 or 06) 16 blocked (11); 17 taken; 18 blocked (11) 25 taken; 26 blocked (71) |
| 2 | Col 9 | 18 |
09 blocked (05); 27 taken 36 taken; 45 blocked (37); 54 taken 63 blocked (58); 72 blocked (65); 81 taken |
| 3 | Cell 8 | 77 |
58 taken; 59 taken; 60 taken 67 blocked (49); 68 taken; 69 blocked (24) 76 blocked (49); 78 blocked (24) |
| 7 | Cell 5 | 50 |
blocked to 1 (46/68); 2 (05/33); 3 (49/77) 4 (47); 5 (14); 6 (48) 8 (32/54); 9 (59) |
| 7 | Cell 3 | 26 |
in Cell 2: 04 blocked (01); 05 taken; 06 blocked (01) 14 taken 22 taken; 23 blocked (50); 24 taken therefore: the 7 for Cell 2 must go 13 or 15 - whichever, the rest of Row 2 is blocked in Cell 3: 07 blocked (01); 08 blocked (01); 09 blocked (01) 16 blocked (13 or 15); 17 taken; 18 taken 25 taken; 27 taken |
| 1 | Cell 9 | 62 |
blocked to 2 (58); 3 (44) 4 (57); 5 (55/81); 6 (60) 7 (26); 8 (17/61); 9 (59/71) |
| 1 | Cell 3 | 09 |
07 blocked (34); 08 blocked (62) 16 blocked (34); 17 taken; 18 taken 25 taken; 26 taken; 27 taken |
| 3 | Row 1 | 07 |
01 taken; 02 taken; 03 taken 04 blocked (24/49); 05 taken; 06 blocked (24) 08 blocked (44); 09 taken |
| 1 | Row 3 | 20 |
19: 1 is blocked (46); 2 (21/37); 3 (24) 5 (02/25/55) 7 (01/26); 8 (03/22); 9 (11/27) 23: 1 is blocked (68); 2 (05/21); 3 (24/77) 5 (14/25) 7 (26/50); 8 (22/32); 9 (27/59) therefore: 4 and 6 each must go 19 or 23 - whichever, the rest of Row 3 is blocked to these digits (= a couple) 20: 2 is blocked (21/65); 3 (24) 4 (19 or 23); 5 (02/25); 6 (19 or 23) 7 (01/26); 8 (03/22/38); 9 (11/27) |
| 3 | Cell 1 | 12 |
blocked to 1 (20); 2 (18/21) 4 (57); 5 (02/14); 6 (48) 7 (01); 8 (03/17); 9 (11) |
| 7 | Cell 7 | 66 |
blocked to 1 (68); 2 (21/65); 3 (12) 4 (57); 5 (55); 6 (48) 8 (03); 9 (71) |
| 3 | Cell 7 | 56 |
blocked to 1 (20/62); 2 (58/65) 4 (47/57); 5 (02/55); 6 (60) 7 (66); 8 (38/61); 9 (11/59) |
| 7 | Row 7 | 63 |
the only digit not placed Row 7 is complete |
| 7 | Cell 6 | 43 |
34 taken; 35 blocked (26); 36 taken 44 taken; 45 blocked (63) 52 blocked (50); 53 blocked (26/50); 54 taken |
| 7 | Cell 4 | 29 |
28 blocked (01); 30 blocked (66) 37 taken; 38 taken; 39 blocked (43/66) 46 taken; 47 taken; 48 taken |
| 6 | Col 2 | 74 |
the only digit not placed Column 2 is complete |
| 3 | Cell 4 | 28 |
29 taken; 30 blocked (12) 37 taken; 38 taken; 39 blocked (12/44) 46 taken; 47 taken; 48 taken |
| 3 | Cell 9 | 72 |
61 taken; 62 taken; 63 taken 70 blocked (07); 71 taken 79 blocked (07/77); 80 blocked (44/77); 81 taken Digit 3 in every cell |
| 6 | Col 9 | 45 |
the only digit not placed Column 9 is complete |
| 6 | Cell 9 | 70 |
61 taken; 62 taken; 63 taken 71 taken; 72 taken 79 blocked (74); 80 blocked (74); 81 taken |
| 6 | Cell 3 | 08 |
07 taken; 09 taken 16 blocked (70); 17 taken; 18 taken 25 taken; 26 taken; 27 taken |
| 4 | Cell 3 | 16 |
the only digit not placed Cell 3 is complete |
| 4 | Cell 1 | 19 |
01 taken; 02 taken; 03 taken 10 blocked (16); 11 taken; 12 taken 20 taken; 21 taken |
| 6 | Cell 1 | 10 |
the only digit not placed Cell 1 is complete |
| 6 | Row 3 | 23 |
the only digit not placed Row 3 is complete |
| 4 | Col 5 | 41 |
the only digit not placed Column 5 is complete |
| 5 | Cell 6 | 35 |
blocked to 1 (34/62); 2 (33); 3 (28/44) 4 (36); 6 (08/45) 7 (26/29/43); 8 (17/32/54); 9 (71) |
| 9 | Cell 6 | 52 |
34 taken; 35 taken; 36 taken 43 taken; 44 taken; 45 taken 53 blocked (71); 54 taken |
| 2 | Cell 6 | 53 |
the only digit not placed Cell 6 is complete |
| 5 | Row 6 | 51 |
the only digit not placed Row 6 is complete |
| 2 | Col 7 | 79 |
the only digit not placed Column 7 is complete Digit 2 in every cell |
| 4 | Col 8 | 80 |
the only digit not placed Column 8 is complete Cell 9 is complete |
| 6 | Cell 5 | 31 |
32 taken; 33 taken 40 blocked (45); 41 taken; 42 blocked (45) 49 taken; 50 taken; 51 taken Digit 6 in every cell |
| 8 | Cell 7 | 64 |
blocked to 1 (46/68); 2 (37/58/65); 3 (28/56/72) 4 (19); 5 (55); 6 (10/70/74) 7 (01/66); 9 (71) |
| 9 | Col 1 | 73 |
the only digit not placed Column 1 is complete |
| 1 | Cell 7 | 75 |
the only digit not placed Cell 7 is complete |
| 5 | Row 5 | 39 |
40: 2 is blocked (33/37/58); 3 (44/49) 4 (41); 5 (51); 6 (31/45) 7(43/50); 8 (22/32/38) 42: 2 is blocked (33/37); 3 (24/44/49) 4 (41); 5 (51): 6 (31/45/60) 7 (43/50); 8 (32/38) therefore: 1 and 9 each must go 40 or 42 - whichever, the rest of Row 5 is blocked to these digits (= a couple) 39: 1 is blocked (40 or 42/46/75); 2 (21/37); 3 (12/28/44) 4 (41/47/57); 6 (45/48) 7 (29/43/66); 8 (03/38); 9 (40 or 42) |
| 9 | Cell 4 | 30 |
the only digit not placed Cell 4 is complete Row 4 is complete Column 3 is complete |
| 7 | Cell 8 | 76 |
blocked to 1 (68/75); 2 (58/79); 3 (49/77) 4 (80); 5 (81); 6 (31/60/74) 8 (22); 9 (59/73) |
| 8 | Row 9 | 78 |
the only digit not placed Row 9 is complete Digit 8 in every cell |
| 7 | Cell 2 | 15 |
04 blocked (01/76); 05 taken; 06 blocked (01) 13 blocked (76); 14 taken 22 taken; 23 taken; 24 taken Digit 7 in every cell |
| 1 | Row 2 | 13 |
the only digit not placed Row 2 is complete |
| 1 | Cell 5 | 42 |
31 taken; 32 taken; 33 taken 40 blocked (13); 41 taken 49 taken; 50 taken; 51 taken Digit 1 in every cell |
| 9 | Cell 5 | 40 |
the only digit not placed Cell 5 is complete Row 5 is complete |
| 9 | Cell 2 | 06 |
04 blocked (40); 05 taken 13 taken; 14 taken; 15 taken 22 taken; 23 taken; 24 taken Digit 9 in every cell |
| 4 | Cell 2 | 04 |
the only digit not placed Cell 2 is complete Row 1 is complete |
| 5 | Col 4 | 67 |
the only digit not placed Column 4 is complete Digit 5 in every cell |
| 4 | Cell 8 | 69 |
the only digit not placed Cell 8 is complete Row 8 is complete Column 6 is complete Digit 4 in every cell The grid is complete |
print out EXAMPLE 2 puzzle grid
| digit | context | square | because |
| 1 | Cell 5 | 33 |
31 taken; 32 blocked (77) 40 taken; 41 blocked (77); 42 taken 49 blocked (53); 50 blocked (53/77); 51 taken |
| 4 | Cell 5 | 49 |
31 taken; 32 blocked (05); 33 taken 40 taken; 41 blocked (05/39); 42 taken 50 blocked (05); 51 taken |
| 6 | Cell 5 | 41 |
31 taken; 32 blocked (28); 33 taken 40 taken; 42 taken 49 taken; 50 blocked (54); 51 taken |
| 7 | Cell 6 | 44 |
34 blocked (29); 35 blocked (29); 36 blocked (29/63) 43 taken; 45 blocked (63) 52 blocked (51); 53 taken; 54 taken |
| 5 | Cell 8 | 59 |
in Cell 5: 31 taken; 33 taken 40 taken; 41 taken; 42 taken 49 taken; 51 taken Digits 3 and 9 to place therefore: 3 and 9 each must go 32 or 50 - whichever, the rest of Column 5 is blocked to these digits (= a couple) in Cell 8 59 blocked to 1 (77); 2 (57); 3 (32 or 50) 4 (05); 6 (41/67): 7 (63) 8 (62); 9 (32 or 50) |
| 9 | Cell 6 | 45 |
in Row 4: 30 blocked to 1 (33); 2 (57) 4 (39); 5(31); 6 (28) 7 (29); 8 (12) therefore: 3 or 9 must go 30 also: 3 or 9 must go 32 (see previous step) - whichever, the rest of Row 4 is blocked to these digits (= a couple) in Cell 6: 34 blocked (25/30 or 32); 35 blocked (30 or 32); 36 blocked (30 or 32) 43 taken; 44 taken 52 blocked (25); 53 taken; 54 taken |
| 3 | Cell 6 | 52 |
34 blocked (30 or 32); 35 blocked (17/30 or 32); 36 blocked (30 or 32) 43 taken; 44 taken; 45 taken 53 taken; 54 taken |
| 9 | Cell 5 | 50 |
blocked to 1 (33/53/77); 2 (40); 3 (52) 4 (05/49); 5 (31/59); 6 (41/54) 7 (51); 8 (42) |
| 3 | Cell 5 | 32 |
the only digit not placed Cell 5 is complete |
| 9 | Row 4 | 30 |
remaining half of couple (see earlier) |
| 9 | Cell 9 | 80 |
61 blocked (25); 62 taken; 63 taken 70 taken; 71 blocked (65); 72 blocked (45/65) 79 blocked (25); 81 blocked (45) |
| 5 | Cell 4 | 48 |
blocked to 1 (53); 2 (57); 3 (52) 4 (39/49); 6 (28/54) 7 (29/51); 8 (12); 9 (30/50) |
| 6 | Row 2 | 11 |
in Cell 9: 62 taken; 63 taken 70 taken; 71 blocked (67); 72 blocked (54/67) 80 taken; 81 blocked (54) therefore: the 6 for Cell 9 must go 61 or 79 - whichever, the rest of Column 7 is blocked in Row 2: 10 blocked (28); 12 taken 13 blocked (67); 14 blocked (41); 15 taken 16 blocked (61 or 79); 17 taken; 18 blocked (54) |
| 4 | Cell 1 | 10 |
01 blocked (05); 02 blocked (05); 03 blocked (05/39) 11 taken; 12 taken 19 taken; 20 taken; 21 blocked (39) |
| 9 | Cell 1 | 01 |
02 blocked (65); 03 blocked (30) 10 taken; 11 taken; 12 taken 19 taken; 20 taken; 21 blocked (25/30) |
| 2 | Cell 1 | 02 |
01 taken; 03 blocked (57) 10 taken; 11 taken; 12 taken 19 taken; 20 taken; 21 blocked (57) |
| 2 | Cell 4 | 46 |
28 taken; 29 taken; 30 taken 37 blocked (40); 38 blocked (02/40); 39 taken 47 blocked (02); 48 taken |
| 8 | Row 6 | 47 |
the only digit not placed Row 6 is complete |
| 6 | Cell 7 | 75 |
55 blocked (28); 56 blocked (11); 57 taken 64 blocked (28/67); 65 taken; 66 blocked (67) 73 blocked (28); 74 blocked (11) |
| 6 | Cell 9 | 61 |
62 taken; 63 taken 70 taken; 71 blocked (67); 72 blocked (54/67) 79 blocked (75); 80 taken; 81 blocked (54/75) |
| 7 | Cell 7 | 66 |
55 blocked (19/63); 56 blocked (29/63) 57 taken 64 blocked (19); 65 taken 73 blocked (19); 74 blocked (29); 75 taken |
| 7 | Cell 8 | 76 |
58 blocked (63); 59 taken; 60 blocked (51/63) 67 taken; 68 blocked (66); 69 blocked (51/66) 77 taken; 78 blocked (51) |
| 7 | Cell 2 | 14 |
04 blocked (76); 05 taken; 06 blocked (51) 13 blocked (76); 15 taken 22 blocked (19/76); 23 blocked (19); 24 blocked (19/51) |
| 7 | Cell 3 | 07 |
08 blocked (44); 09 blocked (63) 16 blocked (14); 17 taken; 18 blocked (14/63) 25 taken; 26 blocked (19/44); 27 blocked (19/63) Digit 7 in every cell |
| 2 | Cell 3 | 16 |
blocked to 1 (70); 3 (17/52) 4 (10); 5 (15/43); 6 (11/61) 7 (07/14); 8 (12); 9 (25) |
| 1 | Cell 3 | 18 |
blocked to 2 (16); 3 (17) 4 (10); 5 (15); 6 (11/54) 7 (07/63); 8 (12); 9 (25/45) |
| 9 | Row 2 | 13 |
the only digit not placed Row 2 is complete |
| 4 | Cell 9 | 79 |
blocked to 1 (70/77); 2 (16); 3 (52) 5 (43); 6 (61/75) 7 (07/63/76); 8 (62); 9 (25/80) |
| 8 | Col 7 | 34 |
the only digit not placed Column 7 is complete |
| 4 | Cell 7 | 56 |
55 blocked (10); 57 taken 64 blocked (10); 65 taken; 66 taken 73 blocked (10/79); 74 blocked (79); 75 taken |
| 3 | Cell 7 | 74 |
blocked to 1 (77); 2 (02/57) 4 (56/79); 5 (20); 6 (11/75) 7 (29/66/76); 8 (47); 9 (65/80) |
| 1 | Col 2 | 38 |
the only digit not placed Column 2 is complete |
| 3 | Cell 4 | 37 |
the only digit not placed Cell 4 is complete Row 5 is complete |
| 1 | Cell 7 | 55 |
56 taken; 57 taken 64 blocked (70); 65 taken; 66 taken 73 blocked (77); 74 taken; 75 taken |
| 3 | Cell 8 | 58 |
blocked to 1 (55/77); 2 (40/57) 4 (49/56); 5 (31/59); 6 (61/67) 7 (63/76); 8 (62); 9 (13) |
| 9 | Row 7 | 60 |
the only digit not placed Row 7 is complete Digit 9 in every cell |
| 4 | Cell 8 | 69 |
58 taken; 59 taken; 60 taken 67 taken; 68 blocked (05) 76 taken; 77 taken; 78 blocked (79) |
| 8 | Cell 8 | 68 |
58 taken; 59 taken; 60 taken 67 taken; 69 taken 76 taken; 77 taken; 78 blocked (42) |
| 2 | Cell 8 | 58 |
the only digit not placed Cell 8 is complete |
| 8 | Cell 7 | 73 |
55 taken; 56 taken; 57 taken 64 blocked (68); 65 taken; 66 taken 74 taken; 75 taken |
| 5 | Cell 7 | 64 |
the only digit not placed Cell 7 is complete Column 1 is complete |
| 5 | Row 9 | 81 |
the only digit not placed Row 9 is complete |
| 3 | Cell 9 | 72 |
61 taken; 62 taken; 63 taken 70 taken; 71 blocked (17) 79 taken; 80 taken; 81 taken |
| 2 | Cell 9 | 71 |
the only digit not placed Cell 9 is complete Row 8 is complete |
| 2 | Cell 6 | 36 |
34 taken; 35 blocked (71) 43 taken; 44 Taken; 45 taken 52 taken; 53 taken; 54 taken |
| 4 | Cell 6 | 35 |
the only digit not placed Cell 6 is complete Row 4 is complete |
| 2 | Col 5 | 23 |
the only digit not placed Column 5 is complete Digit 2 in every cell |
| 4 | Cell 3 | 27 |
07 taken; 08 blocked (05/35); 09 blocked (05) 16 taken; 17 Taken; 18 taken 25 taken; 26 blocked (35) Digit 4 in every cell |
| 8 | Col 9 | 09 |
the only digit not placed Column 9 is complete |
| 5 | Cell 3 | 08 |
07 taken; 09 taked 16 taken; 17 Taken; 18 taken 25 taken; 26 blocked (20); 27 taken Digit 5 in every cell |
| 6 | Cell 3 | 26 |
the only digit not placed Cell 3 is complete Column 8 is complete |
| 8 | Cell 2 | 22 |
04 blocked (09); 05 taken; 06 blocked (09/42) 13 taken; 14 Taken; 15 taken 23 taken; 24 blocked (42) Digit 8 in every cell |
| 1 | Col 4 | 04 |
the only digit not placed Column 4 is complete |
| 1 | Cell 1 | 21 |
01 taken; 02 taken; 03 blocked (04) 10 taken; 11 Taken; 12 taken 19 taken; 20 taken Digit 1 in every cell |
| 3 | Row 3 | 24 |
the only digit not placed Row 3 is complete |
| 3 | Cell 1 | 03 |
the only digit not placed Cell 1 is complete Column 3 is complete Digit 3 in every cell |
| 6 | Cell 2 | 06 |
the only digit not placed Cell 2 is complete Row 1 is complete Column 6 is complete Digit 6 in every cell The grid is complete |
print out EXAMPLE 3 puzzle grid
| digit | context | square | because |
| 1 | Cell 9 | 79 |
61 taken; 62 blocked (26); 63 blocked (54) 70 blocked (64); 71 blocked (26/64); 72 blocked (54/64) 80 blocked (26); 81 taken |
| 2 | Cell 6 | 45 |
in Cell 3: 07 blocked (61); 09 taken 16 blocked (61); 18 taken 25 blocked (21/61); 26 taken; 27 blocked (21) therefore: the 2 for Cell 3 must go 08 or 17 - whichever, the rest of Column 8 blocked in Cell 6: 34 taken; 35 blocked (08 or 17/33); 36 blocked (33) 43 blocked (61); 44 blocked (08 or 17) 52 blocked (61); 53 taken; 54 taken |
| 2 | Cell 4 | 46 |
in Cell 7: 55 blocked (61); 56 taken; 57 blocked (21/61) 64 taken; 66 blocked (21) 73 taken; 75 blocked (21) therefore: the 2 for Cell 7 must go 65 or 74 - whichever, the rest of Column 2 is blocked in Cell 4: 28 taken; 29 taken; 30 blocked (21/33) 37 blocked (45); 38 blocked (45/65 or 74); 39 blocked (21/45) 47 blocked (65 or 74); 48 taken |
| 4 | Cell 6 | 36 |
blocked to 1 (54); 2 (33/45); 3 (28) 5 (53); 6 (09) 7 (29); 8 (18); 9 (34/81) |
| 5 | Cell 8 | 78 |
in Cell 9: 61 taken; 62 blocked (53/56); 63 blocked (56) 71 blocked (53) 79 taken; 80 blocked (53); 81 taken therefore: the 5 for Cell 9 must go 70 or 72 - whichever, the rest of Row 8 is blocked in Cell 8: 58 blocked (56); 59 taken; 60 blocked (56) 67 blocked (70 or 72); 68 taken; 69 blocked (70 or 72) 76 taken; 77 blocked (14) |
| 7 | Cell 9 | 63 |
blocked to 1 (54); 2 (45/61); 3 (59) 4 (36); 5 (56); 6 (09) 8 (18); 9 (81) |
| 1 | Cell 5 | 32 |
blocked to 2 (33); 3 (28/59) 4 (36); 5 (14); 6 (23/49) 7 (29); 8 (68); 9 (34) |
| 6 | Cell 6 | 35 |
in Cell 9 for Digit 8: 61 taken; 63 taken 70 blocked (68); 71 blocked (68); 72 blocked (18/68) 79 taken; 81 taken therefore: the 8 for Cell 9 must go 62 or 80 - whichever, the rest of Column 8 is blocked in Cell 6: 35 blocked to 1 (26/32/54); 2 (33/45); 3 (28) 4 (36); 5 (53) 7 (29); 8 (62 or 80); 9 (34) |
| 6 | Cell 9 | 70 |
61 taken; 62 blocked (35); 63 taken 71 blocked (35); 72 blocked (09) 79 taken; 80 blocked (35/73); 81 taken |
| 6 | Cell 8 | 60 |
58 blocked (49); 59 taken 67 blocked (49/70); 68 taken; 69 blocked (70) 76 taken; 77 blocked (23/73); 78 taken |
| 1 | Cell 8 | 58 |
59 taken; 60 taken 67 blocked (64); 68 taken; 69 blocked (64) 76 taken; 77 blocked (32/79); 78 taken |
| 1 | Cell 2 | 15 |
04 blocked (58); 05 blocked (32); 06 taken 13 blocked (58); 14 taken 22 blocked (26/58); 23 taken; 24 blocked (26) |
| 4 | Cell 2 | 24 |
04 blocked (01/76); 05 blocked (01); 06 taken 13 blocked (76); 14 taken; 15 taken 22 blocked (76); 23 taken |
| 4 | Cell 3 | 16 |
in Cell 9: 61 taken; 63 taken 70 taken; 72 blocked (36) 79 taken; 80 blocked (76); 81 taken therefore: the 4 for Cell 9 must go 62 or 71 - whichever, the rest of Column 8 blocked in Cell 3: 07 blocked (01); 08 blocked (62 or 71); 09 taken 17 blocked (62 or 71); 18 taken 25 blocked (24); 26 taken; 27 blocked (24/36) |
| 5 | Cell 9 | 72 |
61 taken; 62 blocked (53/56); 63 taken 70 taken; 71 blocked (53) 79 taken; 80 blocked (53/78); 81 taken |
| 3 | Col 9 | 27 |
the only digit not placed Column 9 is complete |
| 7 | Cell 6 | 44 |
in Cell 9 for Digit 3: 61 taken; 62 blocked (59); 63 taken 70 taken; 72 taken 79 taken; 81 taken therefore: the 3 for Cell 9 must go 71 or 80 - whichever, the rest of Column 8 is blocked in Cell 6: 44 blocked to 1 (26/54); 2 (45); 3 (71 or 80) 4 (36); 5 (53); 6 (35) 8 (62 or 80 - see earlier); 9 (34) |
| 9 | Row 7 | 55 |
56 taken; 57 blocked (48) 58 taken; 59 taken; 60 taken 61 taken; 62 blocked (81); 63 taken |
| 7 | Cell 1 | 10 |
blocked to 1 (15/64); 2 (21/46); 3 (28) 4 (01/16); 5 (14); 6 (73) 8 (18); 9 (55) |
| 4 | Cell 4 | 47 |
30: 1 is blocked (32); 2 (21/33/46); 3 (28) 4 (36); 6 (35) 7(29); 9 (34/48) 37: 1 is blocked (64); 2 (45/46); 3 (28) 4 (01); 6 (73) 7 (29/44); 9 (48/55) therefore: 5 and 8 each must go 30 or 37 - whichever, the rest of Cell 4 is blocked to these digits (= a couple) 47: 1 is blocked (54); 2 (46); 3 (28) 5 (30 or 37/53/56); 6 (49) 7 (29); 8 (30 or 37); 9 (48) |
| 7 | Cell 5 | 50 |
blocked to 1 (32/54); 2 (33/46); 3 (59) 4 (47); 5 (14/53); 6 (23/49) 8 (68); 9 (48) |
| 3 | Cell 5 | 51 |
blocked to 1 (15/32/54); 2 (33/46) 4 (24/47); 5 (53/78); 6 (49/60) 7 (50); 8 (06); 9 (48) |
| 8 | Row 6 | 52 |
the only digit not placed Row 6 is complete |
| 3 | Cell 6 | 43 |
the only digit not placed Cell 6 is complete |
| 9 | Cell 5 | 42 |
blocked to 1 (15/32); 2 (33/45); 3 (43/51) 4 (24); 5 (78); 6 (49/60) 7 (44/50); 8 (06) |
| 7 | Col 6 | 69 |
the only digit not placed Column 6 is complete |
| 4 | Cell 5 | 41 |
31 blocked (36/76); 32 taken; 33 taken 40 blocked (76); 42 taken 49 taken; 50 taken; 51 taken |
| 2 | Cell 8 | 77 |
blocked to 1 (32/58/79); 3 (59) 4 (76); 5 (14/78); 6 (23/60/73) 7 (50/69); 8 (68); 9 (81) |
| 9 | Cell 8 | 67 |
the only digit not placed Cell 8 is complete |
| 9 | Col 5 | 05 |
the only digit not placed Column 5 is complete |
| 2 | Cell 7 | 65 |
55 taken; 56 taken; 57 blocked (21/61) 64 taken; 66 blocked (21) 73 taken; 74 blocked (77); 75 blocked (21/77) |
| 7 | Cell 7 | 75 |
55 taken; 56 taken; 57 blocked (63) 64 taken; 65 taken; 66 blocked (69) 73 taken; 74 blocked (29) |
| 9 | Cell 3 | 17 |
07 blocked (05/34); 08 blocked (05); 09 taken 16 taken; 18 taken 25 blocked (34); 26 taken; 27 taken |
| 9 | Cell 1 | 20 |
01 taken; 02 blocked (05); 03 blocked (05/48) 10 taken; 11 blocked (17); 12 blocked (17/48) 19 blocked (55); 21 taken Digit 9 in every cell |
| 2 | Cell 3 | 08 |
07 blocked (61); 09 taken 16 taken; 17 taken; 18 taken 25 blocked (21/61); 26 taken; 27 taken |
| 2 | Cell 2 | 13 |
04 blocked (08); 05 taken; 06 taken 14 taken; 15 taken 22 blocked (21); 23 taken; 24 taken Digit 2 in every cell |
| 3 | Cell 2 | 04 |
05 taken; 06 taken 13 taken; 14 taken; 15 taken 22 blocked (27); 23 taken; 24 taken |
| 7 | Cell 2 | 22 |
the only digit not placed Cell 2 is complete |
| 7 | Cell 3 | 07 |
08 taken; 09 taken 16 taken; 17 taken; 18 taken 25 blocked (22); 26 taken; 27 taken Digit 7 in every cell |
| 5 | Cell 3 | 25 |
the only digit not placed Cell 3 is complete Column 7 is complete |
| 8 | Row 3 | 19 |
the only digit not placed Row 3 is complete |
| 5 | Cell 1 | 03 |
01 taken; 02 blocked (56) 10 taken; 11 blocked (14/56); 12 blocked (14) 19 taken; 20 taken; 21 taken |
| 5 | Cell 4 | 37 |
the only digit not placed Column 1 is complete |
| 8 | Cell 4 | 30 |
remaining half of couple (see earlier) |
| 5 | Cell 5 | 31 |
32 taken; 33 taken 40 blocked (37); 41 taken; 42 taken 49 taken; 50 taken; 51 taken Row 4 is complete Digit 5 in every cell |
| 8 | Cell 5 | 40 |
the only digit not placed Cell 5 is complete Column 4 is complete |
| 8 | Cell 7 | 74 |
55 taken; 56 taken; 57 blocked (30) 64 taken; 65 taken; 66 blocked (30/68) 73 taken; 75 taken |
| 3 | Row 9 | 80 |
the only digit not placed Row 9 is complete |
| 8 | Cell 9 | 62 |
61 taken; 63 taken 70 taken; 71 blocked (68); 72 taken 79 taken; 80 taken; 81 taken Digit 8 in every cell |
| 4 | Cell 9 | 71 |
the only digit not placed Cell 9 is complete Column 8 is complete |
| 4 | Row 7 | 57 |
the only digit not placed Row 7 is complete Digit 4 in every cell |
| 3 | Cell 7 | 66 |
the only digit not placed Cell 7 is complete Row 8 is complete |
| 1 | Row 1 | 02 |
the only digit not placed Row 1 is complete |
| 1 | Cell 4 | 39 |
28 taken; 29 taken; 30 taken 37 taken; 38 blocked (02) 46 taken; 47 taken; 48 taken Digit 1 in every cell |
| 6 | Cell 4 | 38 |
the only digit not placed Cell 4 is complete Row 5 is complete |
| 3 | Col 2 | 11 |
the only digit not placed Column 2 is complete Digit 3 in every cell |
| 6 | Cell 1 | 12 |
the only digit not placed Cell 1 is complete Row 2 is complete Column 3 is complete Digit 6 in every cell The grid is complete |
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