## What is the next move here?

Advanced methods and approaches for solving Sudoku puzzles

### What is the next move here?

It seems to me that there is more than one posibility for the next move, I find it hard to know what. Can you teach me find the options?

[678]9[4678],[478]12,5[46]3
5[24678]1,3[78][48],[678]9[24678]
[2378]]23478][23478],596,[78][24]1

[12367][23467]9,[467][367][34],[1367]85
[3678][34678][3478],251,9[346][467]
[1367]5[347],[4678][3678]9,2[1346]467]

4[2378][3578],9[2368][38],[1368][12356][268]
[238]1[2358],[68][2368]7,4[2356]9
9[238]6,145,[38]7[28]
Kites

Posts: 48
Joined: 20 May 2005

You have a candidate 6 in r1c3 that can't be there (as there's a 6 in r9c3), but it doesn't help much. I put this into Sudoku Susser, which needs Nishio to solve it. In other words, it's really hard. Perhaps someone who understands these ridiculously complex methods can be more helpful.
PaulIQ164

Posts: 533
Joined: 16 July 2005

### Re: What is the next move here?

Kites wrote:It seems to me that there is more than one posibility for the next move, I find it hard to know what. Can you teach me find the options?

[678]9[4678],[478]12,5[46]3
5[24678]1,3[78][48],[678]9[24678]
[2378]]23478][23478],596,[78][24]1

[12367][23467]9,[467][367][34],[1367]85
[3678][34678][3478],251,9[346][467]
[1367]5[347],[4678][3678]9,2[1346]467]

4[2378][3578],9[2368][38],[1368][12356][268]
[238]1[2358],[68][2368]7,4[2356]9
9[238]6,145,[38]7[28]

Have a look at the 2's - there seems to be an 'x-wing' pattern (row 2 and 9) - which means that candidate 2 can be excluded from all cells in column two and nine except those in row 2 and 9.
Ocean

Posts: 442
Joined: 29 August 2005

### Re: What is the next move here?

[quote="Ocean"][quote="Kites"]It seems to me that there is more than one posibility for the next move, I find it hard to know what. Can you teach me find the options?

[678]9[4678],[478]12,5[46]3
5[24678]1,3[78][48],[678]9[24678]
[2378]]23478][23478],596,[78][24]1

[12367][23467]9,[467][367][34],[1367]85
[3678][34678][3478],251,9[346][467]
[1367]5[347],[4678][3678]9,2[1346]467]

4[2378][3578],9[2368][38],[1368][12356][268]
[238]1[2358],[68][2368]7,4[2356]9
9[238]6,145,[38]7[28][/quote]

Have a look at the 2's - there seems to be an 'x-wing' pattern (row 2 and 9) - which means that candidate 2 can be excluded from all cells in column two and nine except those in row 2 and 9.[/quote]

Thank you very much for pointing 'x-wing' - this puzzle is solved now!
Kites

Posts: 48
Joined: 20 May 2005

[quote="PaulIQ164"]You have a candidate 6 in r1c3 that can't be there (as there's a 6 in r9c3), but it doesn't help much. I put this into Sudoku Susser, which needs Nishio to solve it. In other words, it's really hard. Perhaps someone who understands these ridiculously complex methods can be more helpful.[/quote]

Thanks Paul, you were right about the 6.
Kites

Posts: 48
Joined: 20 May 2005