The New Sudoku Players' Forum

[puzzled]

I am fairly new with Sudoku's and thought iwas doing a fairly decent job of solving the "easy" ones that do not require any guessing but I found one that has stumped me.

This is the original puzzle
_ _ _ 3 _ _ 2 _ 1
_ 8 _ 1 _ _ _ _ _
3 _ _ _ _ 6 _ _ _
_ _ 4 9 _ _ _ 2 3
2 _ 8 _ _ _ 7 _ 9
6 7 _ _ _ 1 8 _ _
_ _ _ 6 _ _ _ _ 5
_ _ _ _ _ 9 _ 7 _
1 _ 6 _ _ 3 _ _ _

And here is how far I got before being stumped.

_ 6 _ 3 _ _ 2 _ 1
_ 8 _ 1 _ _ 3 6 7
3 _ 1 _ _ 6 5 _ 8
5 1 4 9 _ _ 6 2 3
2 3 8 _ 6 _ 7 1 9
6 7 9 2 3 1 8 5 4
_ _ _ 6 _ _ _ 3 5
_ _ 3 _ _ 9 _ 7 6
1 _ 6 _ _ 3 _ 8 2

Any ideas?

Thanks[/code]

[Nick67]

Here is the puzzle with candidates showing:

Code: Select all


{479}   {6}     {57}    {3}     {45789} {4578}  {2}     {49}    {1}     
{49}    {8}     {25}    {1}     {2459}  {245}   {3}     {6}     {7}     
{3}     {249}   {1}     {47}    {2479}  {6}     {5}     {49}    {8}     
{5}     {1}     {4}     {9}     {78}    {78}    {6}     {2}     {3}     
{2}     {3}     {8}     {45}    {6}     {45}    {7}     {1}     {9}     
{6}     {7}     {9}     {2}     {3}     {1}     {8}     {5}     {4}     
{4789}  {249}   {27}    {6}     {12478} {2478}  {149}   {3}     {5}     
{48}    {245}   {3}     {458}   {12458} {9}     {14}    {7}     {6}     
{1}     {459}   {6}     {457}   {457}   {3}     {49}    {8}     {2}     


Check for a "hidden single" in column 4.
After that, keep looking for both hidden
and naked singles. I think that'll get you through.

[puzzled]

Thanks for the help Nick67 but I am still struggling.

I am not exactly sure of the difference between a naked a hidden single - I am guessing that is why I don't quite get your hint/help. Can you provide a little more?

Thanks

[puzzled]

Does cell r8, c4 have to be an eight?

[Nick67]

Does cell r8, c4 have to be an eight?

You got it. The 8 in that cell is a "single" because it's
the only 8 candidate in that column. And it's
"hidden" because there are other candidates
for that cell.

A naked single is a single in a cell without
any other candidates.

Whenever you find a single of either type,
you can safely assign that value to the cell.