Help with National 2008 advanced?? How to proceed?

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Help with National 2008 advanced?? How to proceed?

Postby tpatana » Mon Jan 19, 2009 7:35 am

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I tried solving the National 2008 advanced (target 7:38), but I'm stuck at this point. Any help how to proceed?

I tried few online solvers. They either just give the solved result (which doesn't help me learn how to solve it), or they get even lousier option than what I have deducted already. Any help would be appreciated.

Thanks.
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Re: Help with National 2008 advanced?? How to proceed?

Postby eleven » Mon Jan 19, 2009 8:36 am

Look at the pair 59 in column 9 (you have used it in the box only). Another pair then can solve it.

tpatana wrote:I tried few online solvers...
There should be better ones, but i dont have links. Two good (and free) programs, which can help you also for harder puzzles are Sudoku Explainer and JSudoku.
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Re: Help with National 2008 advanced?? How to proceed?

Postby tpatana » Mon Jan 19, 2009 8:45 am

eleven wrote:Look at the pair 59 in column 9 (you have used it in the box only). Another pair then can solve it.


Ah, there is typo in r3c9, there wasn't supposed to be 9 inside.

Oh wait, do you mean that from r7c9 and r9c9, and then r1c1 and r9c1, the 59-pairs force r6c1 to be 8? That'd be correct answer, I'm just not sure about the logic if it works or not??

I'd really like to learn how to solve these really difficult ones, I'm just not there yet:(
tpatana wrote:I tried few online solvers...
There should be better ones, but i dont have links. Two good (and free) programs, which can help you also for harder puzzles are Sudoku Explainer and JSudoku.


Thanks for these, I'll have to take a look.
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Postby DonM » Mon Jan 19, 2009 9:24 am

At first glance: Doesn't exactly blow the puzzle apart, but there is a column-based finned x-wing on 8s c49r34 (purposely reversed), fin at r2c4 => r3c5<>8 and a 2-string kite: (8)r16c1/r5c35: r1c5<>8
Last edited by DonM on Mon Jan 19, 2009 5:43 am, edited 2 times in total.
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Re: Help with National 2008 advanced?? How to proceed?

Postby Luke » Mon Jan 19, 2009 9:25 am

tpatana wrote:Ah, there is typo in r3c9, there wasn't supposed to be 9 inside.
If it's a typo then you're really getting low on options for that 9 in r3 or box 3....
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Re: Help with National 2008 advanced?? How to proceed?

Postby tpatana » Mon Jan 19, 2009 9:33 am

Luke451 wrote:
tpatana wrote:Ah, there is typo in r3c9, there wasn't supposed to be 9 inside.
If it's a typo then you're really getting low on options for that 9 in r3 or box 3....


You're right.

And with the help of the Sudoku Explainer (posted by eleven), there were several hidden singles out there, which opened it up quite easily.

Need bigger paper, this one was way too messy to find out those by myself:(

Thanks for the help guys. Now I just need to learn to crack this in 7:38 by pure logical reasoning.
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