The New Sudoku Players' Forum

[Croucher]

I thought I was good at solving sudokus but this one from the Bangkok Post, Jan 22, has me stuck at the following position.

5 8 1 / 6 - - / 7 - -
6 - - / 7 5 - / - - 4
- - 9 / - - 3 / 5 - 6
---------------------
- - 8 / 5 - - / 3 6 2
- 1 - / 3 - - / - 7 5
3 5 - / - - - / 1 4 -
---------------------
2 6 5 / 1 - - / 4 - -
8 9 7 / 4 3 6 / 2 5 1
1 - - / - - 5 / 6 9 -
-----------------------

Apologies for not setting it out properly, but I can see no forum guidance about how to do it. Anyway, I hope someone can suggest the next move as I have been staring at the above for many hours over several days now!

[Carcul]

Hi Croucher.

The only place for "9" in column 4 is in cell r6c4. This should make easy the solving of the remaining puzzle.

Regards, Carcul

[CathyW]

Hi Croucher

There's a sticky thread at the top of the "Help with particular puzzles" forum. You need to use the Code button having first set out your puzzle using a fixed pitch font, such as courier, in Word or similar (or using Simple Sudoku to dub in your puzzles you can copy your grid and paste within 'Code' which is what I've done below). It also helps if you can post the original puzzle and your candidate list so we can see what eliminations you've already made.

Your puzzle:

Locked candidates (2s) in box 6 - therefore r2c3 = 3

You can use the uniqueness principle to determine that r4c1 = 9 (otherwise the puzzle would have at least two solutions because r3c1,2 and r4c1,2 would be interchangeable).

Grid now looks like this:

Code: Select all

 
 *-----------*
 |581|6..|7..|
 |623|75.|..4|
 |749|..3|5.6|
 |---+---+---|
 |978|5..|362|
 |41.|3..|.75|
 |35.|...|14.|
 |---+---+---|
 |265|1..|4..|
 |897|436|251|
 |134|..5|69.|
 *-----------*

{5}     {8}     {1}     {6}     {249}   {249}   {7}     {23}    {39}   
{6}     {2}     {3}     {7}     {5}     {189}   {89}    {18}    {4}     
{7}     {4}     {9}     {28}    {128}   {3}     {5}     {128}   {6}     
{9}     {7}     {8}     {5}     {14}    {14}    {3}     {6}     {2}     
{4}     {1}     {26}    {3}     {2689}  {289}   {89}    {7}     {5}     
{3}     {5}     {26}    {289}   {26789} {2789}  {1}     {4}     {89}   
{2}     {6}     {5}     {1}     {789}   {789}   {4}     {38}    {378}   
{8}     {9}     {7}     {4}     {3}     {6}     {2}     {5}     {1}     
{1}     {3}     {4}     {28}    {278}   {5}     {6}     {9}     {78}   


The rest can be done with singles!

Hope that's what you wanted.

Edit: Carcul got there before I'd finished setting this out - spotting that single in column 4 in the first place is much quicker!!

[Crazy Girl]

Croucher,

Check out the link below on how to use BBCode.
http://forum.enjoysudoku.com/faq.php?mode=bbcode

[Croucher]

Thanks to all for putting me out of my misery. It took me a few minutes to realise why Carcul was so sure that c4r6 had to be a 9. He could see that if two cells have candidates 2 and 8, and the one remaining cell 2,8,9, then the 9 is sure to be in the third cell. Believe it or not, I've been solving sudokus up to now without using that simple technique. I've a feeling I will find them a bit easier in future.