The New Sudoku Players' Forum

[Hugh]

I am completely stumped on this one. Have managed to fill in a few numbers but have hit a wall. Can anyone offer some hints? Thanks in advance.

[Animator]

If you post your current grid (and your current pencilmarks) then someone will help you...

[CathyW]

I missed the Sunday Times this week so just got it from the website. The grid is as follows:

Code: Select all

 *-----------*
 |...|9.3|...|
 |.1.|.8.|.6.|
 |..9|4.6|2..|
 |---+---+---|
 |.24|...|83.|
 |3..|...|..5|
 |.57|...|42.|
 |---+---+---|
 |..5|8.2|1..|
 |.7.|.3.|.5.|
 |...|5.7|...|
 *-----------*


{245678} {468}    {268}    {9}      {1257}   {3}      {57}     {1478}   {1478}   
{2457}   {1}      {23}     {27}     {8}      {5}      {3579}   {6}      {3479}   
{578}    {38}     {9}      {4}      {157}    {6}      {2}      {178}    {1378}   
{169}    {2}      {4}      {167}    {15679}  {159}    {8}      {3}      {1679}   
{3}      {689}    {168}    {1267}   {124679} {1489}   {679}    {179}    {5}     
{1689}   {5}      {7}      {136}    {169}    {189}    {4}      {2}      {169}   
{469}    {3469}   {5}      {8}      {469}    {2}      {1}      {479}    {34679} 
{124689} {7}      {1268}   {16}     {3}      {149}    {69}     {5}      {24689} 
{124689} {34689}  {12368}  {5}      {1469}   {7}      {369}    {489}    {234689}


Wasn't that bad - after placing the 5 in row 2, next step was to exclude some 1s (locked candidates in box 2). Several more exclusions - look for a triple in column 5 and an x-wing (4s).

Let us know how you get on.

Cathy

[Crazy Girl]

Hugh,
After basic sudoku techniques you should reach this point:
(If stuck with the terminology look here and here)

Code: Select all

 . . . | 9 . 3 | 5 . .
 . 1 . | . 8 5 | . 6 .
 5 . 9 | 4 . 6 | 2 . .
-------+-------+------
 . 2 4 | . 5 . | 8 3 .
 3 . . | . . . | . . 5
 . 5 7 | 3 . . | 4 2 .
-------+-------+------
 . . 5 | 8 . 2 | 1 . .
 . 7 . | . 3 . | . 5 .
 . . . | 5 . 7 | . . .

with this candidate grid

Code: Select all

+----------------------+-------------------+--------------------+
| 24678  468    268    | 9     127   3     | 5    1478  178    |
| 247    1      23*    | 27    8     5     | 379* 6     3479    |
| 5      38^    9      | 4     17    6     | 2    178   1378^   |
+----------------------+-------------------+--------------------+
| 169    2      4      | 167   5     19    | 8    3      1679  |
| 3      689    168    | 1267  24679 1489  | 679  179    5      |
| 1689   5      7      | 3     69    189   | 4    2      169    |
+----------------------+-------------------+--------------------+
| 469    3469^  5      | 8     469   2     | 1    479    34679^ |
| 124689 7      28     | 16    3     149   | 69   5      24689  |
| 124689 34689  12368* | 5     469   7     | 369* 489    234689 |
+----------------------+-------------------+--------------------+

there are 2 X-Wings in 3's marked above with * & ^, thus allowing one to remove 3's in R9 and C9. (No real use in solving the grid, but good fun to hunt for )
Then a naked {4, 6, 9} triple in Column 5, leaving a Naked/Hidden {1, 2, 7} triple, now able to place 4 in block 5 so R5C6=4. This leads to the following candidate grid.

Code: Select all

+----------------------+------------------+--------------------+
| 24678 468    268     | 9      127   3   | 5     1478  1478  |
| 247~  1      23*     | 27     8     5   | 379*  6     479~  |
| 5     38*    9       | 4      17    6   | 2     178   1378*  |
+----------------------+------------------+--------------------+
| 169   2      4       | 167    5     19  | 8     3     1679  |
| 3     689    168     | 1267   27    4   | 679   179   5      |
| 169   5      7       | 3      69    8   | 4     2     169    |
+----------------------+------------------+--------------------+
| 469    3469*  5      | 8      469   2   | 1     479   34679* |
| 24689~ 7      28     | 16     3     19  | 69    5     24689~ |
| 124689 4689   12368* | 5      469   7   | 369*  489   24689  |
+----------------------+------------------+--------------------+


Now an X-Wing in 4 shown with ~, allowing further deductions of candidates,
Then there are 2 Naked triples, one in Row 8, the other Column 1.
This leads to the placement of 1 in Block 7.

If you are still stuck let us know and someone will point you in the right direction.